Mostly, it's about making Iops more like.. well, Iops. It's been a *long* time since I saw the show, but as far as I can recall things, Iops are meant to be knights and guardians of Shushu (demons), meant to keep them restrained. They are chivalrous weaponmasters who sometimes become possessed by the shushu they're keeping locked up in their weapons.. and presently, Wakfu doesn't mechanically reflect ANY of that.
So here's some food for thought. Bear in mind it's from an Iop..
Let's change up the passives!
Virility: Currently gives +20% Max HP maxed out. This is not bad (every Iop should take it, no doubt), but at the same time it's obviously got room for improvement: Just look at similar HP buffs from any other class. Give it +1 Resistance to all damage types per rank, for 20% res all at max rank. Done deal. Nothing major, but a helpful little bit that makes Iops slightly better at soaking damage. They're not meant to be tanks, but they are meant to be able to take hits.
Compulsion: +40% general damage buff. Good passive, but also fairly boring. This is something that can be easily changed to make it more Iop-thematic. Change the name of it to Weapon Master, and add to it that every rank gives 2% of your weapon(s) base damage as an additional amount of elemental damage. This means that at rank 20, it will give 40% dmg + 40% of your weapon(s) base damage as an extra amount (including a dagger, if you happen to have one in the offhand). Realistically this will not be a huge amount even at the endgame at present, and by its nature it scales to the environment you're in (so it won't be overpowering low-end, and it will be considered a small amount late-game). It still might be necessary to lower the 40% general damage down to compensate if it's too much damage with both at 40%, but I think it'd be a decent tradeoff even so. And now it fits what an Iop is. You can take more advantage of it by wearing a dagger, or forego a small amount of +dmg for more defense, which is helped by virility further.
Authority: They finally removed all mentions of facing from it just recently, and that suits me just fine. I don't agree with the 3/turn limit, but whatever. It's generally good enough as it is; consider possibly buffing it so that the 10% chance to clap gives allies +5% crit for the next turn, making the clapping meaningful mechanically. Otherwise fine.
Showoff: Great in groups where you'll typically find it maxed out every turn, worthless if you're soloing. My main issue is that it's a damage buff when you already have other sources for this--it's more of the same, and it's unreliable to attain and not hugely noticed when you have it. That should change. For this reason, Preparation as a buff should change from +1% dmg to the next attack to be +1 critical hit chance, which lasts until you next crit. It still caps at 100% (ensuring a crit on your next attack), and it only lasts for one attack, but it should be more meaningful now. It should not only be if an ally kills an enemy, but whenever ANY enemy dies, allowing solo iops to now find *some* use in the skill.
Locking Pro: Easily the weakest Iop passive unless you solely PvP, and even then it is still the lowest. It would only be above Showoff if you duel and don't expect to have any allies in your fights, and with the multitude of multiclienting, that is rare. This skill needs help. Rename it Shushu Guardian for flavor, and give it some interesting mechanics. Give it +2.5 Lock/rank (+50 Lock rank at max), and give it some kind of interesting effect in addition to Iop-bound (which should stay, and should still keep its every-other-turn immunity effect to counterbalance itself). One of these two I think would be good:
* Make it so that at rank 20, Iops now lock all 8 squares around themself, rather than just the adjacent four. It would be a hindrance to enemes trying to move around the Iop, and give Iops more battlefield presence (especially in groupds, where you could make a 'hold the line' scenario with 2-3 iops--really cool stuff!). They aren't necessarily tanks, but neither should you just easily go around them to something else. For non-teleporting, non-pushback enemies (which there are not a ton of being made at higher levels, to keep this all in perspective) it means they have to have two lock checks in most cases to go past the Iop. This option also indirectly buffs standard bearer, just by making its stabilization ability meaningful as the Iop's area of influence expands, and with SB you can ensure it's where you want.
* Alternatively, make it so that anyone who fails a lock check against the Iop is automatically struck by the Iop's mainhand weapon, without the Iop spending any AP/MP/WP/etc. Free weapon hit any time they manage to keep something in front of them--think D&D and an AoO.
Either one works to make Locking Pro actually worthwhile. I suspect doing both would make it just plain doing too much at that point, and I'm undecided. In general it'd be nice just to see the Iop's passives be more interesting in gameplay. They don't need to be hugely complex like foggers, fecas or what-have-you, they just need to do more than they are now.
Jump: Great skill. Pretty much always picked in favor of Flatten because you can't stun yourself with it, it costs less, it can ignore obstacles, and it gives you a damage buff. At the same time, the damage buff is minor now (I'm fairly certain it used to give +50% preparation, and before that just +50% damage to the next attack unlinked to prep), and it is a very costly skill for how little movement you're getting: 2 MP for 2 AP and 1 WP. Not very great in the scheme of things. Remove the power buff, set the limit at 2/turn, and drop the 2 AP. 1 WP for 2 spaces with no LOS at rank 9.
Defensive Stance: Pretty decent skill all in all. They recently lowered it from 50 block to 40 block at max rank, and I'm not huge on that change, but it is still a fairly respectable skill. It suffers from the same sort of thing that compulsion and virility do, though--it's great and absolutely worth taking, but it could be doing more and not be broken at all. Give it +20 Lock at rank 9, and and an added benefit that if anyone critically hits the Iop while they're in D-stance, the Iop gains +20 Preparation (the new version). Makes it more powerful, but balances it around the shared status with Showoff--if Showoff is already maxed, you gain no benefit.
Flatten: Oh, Flatten. I want to like you. Well, really, I do like flatten. It just isn't as good as Jump, and really isn't that much better than charges that you already find in your elemental trees. It has two more range than charge/SIP, costing the same, but it requires points better spent in other specialties and it can end your turn with you having done nothing *but* close in on an enemy, even maxed. Most people I think would rather save 18 levels worth of specialty points and use a Jump + SIP/Charge instead of flatten. Even at max rank it requires LOS, which you can frequently find yourself lacking if you're the full 5 squares away.
tl;dr ditch Flatten. It's time to make room for a new, interesting speciality: Shushu Possession. Iops deserve this, okay. It's a defining class thematic, as much as if not more than similar class transformations (drhellzerker, osa possession, etc). For what it does, however, I'm still at a loss here. I'm only an Iop, after all. Something like..
1 WP transformation (and some splattering of AP that reduces as it ranks up). +100% weapon base damage to all elemental damages (stacking with the passive), but makes your weapon unusable in this state. -20% Res all while in this state, but elemental attacks while possessed use the target's weakest elemental resistance, regardless of the Iop's elemental damage type for their attack.
IDK man, I know I want shushu possession. I don't know mechanically how it should work in a way that is distinct to itself and to Iops as a defining feature.
Bravery Standard: It's okay, but really, the best part of about it is *still* that it stabilized the Iop, and that's not even what the skill is really meant to be about. Let's change that: Bravery standard's damage buff is now effective to all allies around the map, not just those in close quarters (there's no reason for it to be limited to a 2-tile nearby effect). Lasts until the Iop's next turn and can give a party-wide +50% damage buff. It's cool, but hardly broken. As an added effect, consider making it so that if the Iop is in a guild, the standard the Iop bears is their guild's (ala the guild flag wave emote). Would be a nice touch.
Increase: I haven't done my homework on this skill. As in, I've never used it since it's been changed. From everything I know it's pretty good for what it does, though. My main issue is just that its text is outdated and it should be clearer on what it *actually* does, because the wording is unclear if it *actually* removes the power state to do what it does (Which it does, to my knowledge, by the description makes it sound like it *gives* the power state to you, and is all-around bad). If the increase stun chance doesn't last until you next stun (I think it might just be for the turn?), it should. Otherwise it's fine, and I can't think of much that should be done to it to make it any more Iop-like.
I have issues with the Iop's elemental spells too, but that's another topic for another time. Feel free to critique it and give your thoughts or your own ideas, it's just stuff I've had around and wanted to put to words. I think Iops as a class are great, but I think the present implementation of Wakfu Iops leaves out most of what Iops are in favor of generic melee DPSer that isn't even that great at that anymore. There's plenty of melee DPS, but Iops are knights and shushu guardians, and they desperately need some distinction. More than a power buff, I hope any future revamp of the class adds in some more thematic stuff for them.