I decided to stat 1 AP, 1 range, and 1 MP. I'm now stating initiative up to about 446 (including set initiative bonus) then going crits the rest of the way. Initiative is valuable for raising both your earth and your air damage at the same time using the Initiator bonus. And crits are valuable not only for their high damage but also because they increase the chance that your Air hits can end up nearly free due to returned AP from Rogue Master.
One thing to note is anything above 446 initiative doesn't do you much good (except in PvP maybe) because initiator is capped at 140% damage, which maps out to 467 initiative. So I'm going keep initiative about at 467 max, and if it goes over that because of upgrading to a set with higher init I'll respec and redistribute the extra points from init to crits.
With earth rogue I feel it is very important to stat at least 1 range because your spells are range modifiable. It's nice to be able to hit from a safer distance, and not be quite as crippled if some enemy effect reduces your range a bit.
Machine Gun: low priority, useful for hitting in diagonal sometimes when there is nothing else to hit with, or to finish off a wounded enemy using a low AP attack, but if you focus mainly on this spell you aren't gonna be able to kill stuff very effectively and your attack power is going to suck.
Piercing Shot: Brilliant damage, this is gonna be your primary damage spell at mid game when you can get 10 AP for two casts. Personally I'm not there yet, but with 9 AP I can use a combo of one Piercing and one Blam. But until you can get 9 AP or 10 AP this spell is going to be very ineffective because it will use up 5 AP and only leave you with 2 or 3 left over for a pathetic machine gun shot or some other lame low damage attack. But you better level it anyway because you are going to be loving it later.
Cross Fire: Absolutely worthless for all but the rarest occasions where you can't hit something any other way. I wouldn't even bother wasting spell experience on this unless you have nothing else to level. Its better to distribute experience into air spells instead of focusing on levelling this.
Blam: I love this spell. It's meshes well with a tank character like Sac or a Trank, because the character can get two enemies locked on them, and then the rogue can cast Blam to damage both of the enemies at once. Additionally if someone is tanking a monster it is possible to hide behind them and use Blam to shoot "around" the tank and hit the monster on the far side of the tank. When it is possible to hit multiple enemies this spell gives you way more damage per AP spent than anything else. And if you only have 8 AP like most beginners then two casts of Blam is your most efficient killing combo. Level this early, and as high as you can.
Pulsar: Good spell. It's great for taking stuff out with one impressively high shot, and if you cast Fusilade State and end up left with just tons of MP on the next turn you can use this to deal some nice damage with nothing but MP.
Slap Shot: Almost worthless. I wouldn't bother with this.
Roguery: Worthless. As earth rogue you don't want to get near your enemies, you want them away from you.
Boomerang Arrow: Brilliant spell. Sometimes your allies are noobs and block your Piercing Shot LoS and/or get in locations where they make it impossible to Blam an enemy without hitting them too. Boomerang Arrow is your friend here. Additionally Boomerang Arrow can do some insanely high damage in certain situations where you can exploit its strange AoE to hit multiple enemies. This works best if you and your allies plan well and position yourselves in such a way that when monsters come to fight in CC they end up standing on the arc AoE of your Boomerang Arrow. This is easier to do than you might think. Just place three characters or MM in a pattern like this:
P = tanking player locations
X = where you should stand
M = the monsters that will probably come to attack the tanks and stand right where you want them to be for your Boomerang Arrow.
Hitting four or five monsters at once is beautiful!
Barbecued Ribs: Worthless waste of a WP better spend elsewhere.
Longsword: Best spell ever. It's super expensive but when a nasty enemy gets up in your face, you can deal a huge hit to it while pushing it away one tile so that it can be hit with your earth spells. One combo that is nice when an enemy gets up in your face is one Longsword + Pulsar to deal a death blow using all your MP and leftover AP. Additionally sometimes when enemies line up its effective to run into CC and Longsword them to hit three at once with high damage.
All spells worthless for an earth/air build. Maybe level a couple a little bit for the resistances eventually, but other than that not worth it.
Surprise Shot: Level this first, all the way, its amazing. It's important to note that it is 40% chance of getting a surprise shot per attack, so often times its more effective to do multiple attacks per turn to increase the chances of getting at least one surprise shot rather than entrust all your AP and MP on one single pulsar and then not end up with a Surprise Shot on that expensive spell. Much better to cast two Blam and get a surprise shot on one for example.
Initiator: Second thing I leveled. Nice to have that bit of extra damage from it, and for a hybrid build like we are making it allows you to raise both of your primary damage elements at once using initiative.
Rogue Master: Some extra init that plays nicely with Initiator, and a chance to get AP back for every Air hit? Yes please! There is nothing more fun than doing a Longsword hit, then finding that you hit the jackpot and got 3 AP back and still have enough AP for a piercing shot. One thing to note is you should use an air spell early, if possible as the first thing you do, because that way if you get returned AP you can make the optimal use of it along with the rest of your AP. If you cast the air spell as the last spell and end up with a few AP returned you might have nothing to do with it except for a lame Slap Shot or Machine Gun.
Magnetic Claw: This spell is great when fully leveled but worthless at low levels because of the high cost. Eventually you need it to get stuff away from you when needed or to move an ally. A longsword + a magnetic claw can put two spaces (or three if you are lucky with a Longsword crit) between you and your foe, and then you can still use your MP to run away. This has saved my life before in some fights.
The build that I went with basically just used random crappy gear from the markets that had decent earth/air/init until level 67 when I could equip full Ancestral Treechnid Set + Goultard. This set gives you an MP and an AP from Treechnid, and Goultard gives you an AP. You also have the AP and MP from stats, so I'm now level 71 with 9 AP, 5 MP, and over 200 earth damage, and around 190 air damage. It's a really fun build.
I'm shooting for level 91 and whispering set now, which is when I think my earth/air build is really going to start taking off. I'm also working on a decent way to get 10 AP for two piercing shots, which is should be fun and very deadly. I'll keep you guys updated on my progress and tips from other experienced players are always welcome.
Update Feb 20, 2014:
I'm level 99 now, and got my 10 AP build working quite nicely with the following items: Whispering Set, Gobbsage String, Kraken Eps, The Alphabet Agama, Ancestral Boots and Ring, and Lego Lars Bow. Lego Lar's Bow is an extremely nice AP weapon upgrade when you outgrow Goultard. On Nox it is fairly affordable, only 30,000 - 40,000 in the market when I was buying.
Here is how my stats and spells are shaping up:
As you can see from my spells I have fully leveled all the main specialty skills for earth/air rogue. I'm leveling boombot now. So far I haven't had much use for it, but I figure it will be useful as a distraction in tough dungeons, and for its AoE ability to extend Earth rogue shots.
This post has been edited by Mishna - March 17, 2014, 23:35:25.