I've been an ecaflip right since this game started!!!
I've been through all the ups and downs...trust me you can't learn to play ecaflip in just 1 week or so of your playing time..ecaflips need time understanding combinations that would work perfectly in all situations to increase your damage as well as crits!
In my experience combining water and earth branch can make you an effective damage dealer as well as keep you longer in the game cuz of the heals!
Now my build is Tri-element after the recent update...and i have no too high level gears...just have a moo set plus some fillers! N i think i can dish out about 1200 dmg easy no crit! I am lvl 118 though.
But yea the point is even with shitty gear you can be good. And buddy the example you gave of the osa in pvp!! well a summon osa can pretty much own half the classes in wakfu so I don't think that would be a good example to show your lack of trust in ecaflips' abilites!!
Now I am not gonna give you a guide or anything...you should try different combinations yourself...trust me that would be much more fun that simply copying other!!
- Noob Luck