I'll have to say Water is still my favorite. It's got the perfect balance of move types. High damage moves, moves that cause slowness, defensive moves, knockback moves, etc. Today's new abilities only made me like it even more. WaterWave adds the mobility Water lacked and IceBlast added a powerful move with slowness bonus. Plus, according to one of Mist's goal posts, we still have another move for a new subelement on the way AND an upgrade for a current one.
Water isn't perfect though. OctopusForm is pretty much useless, IceSpike (shift specifically) isn't good for fast pace battles, and the the WaterWave is too slow to actually dodge most attacks with. Hopefully in the coming updates these issues will be fixed. In my opinion some moves could use upgrades (WaterManipulation and Surge) so they have added defense/attack functionality, since Water is supposed to be the perfect balance of offense and defense.
Overall, I think every element is like this. They all have they're strengths and they all have they're weaknesses. Some can be fixed while others will most likely stay there forever, which is good. I guess in the end Water just fits my fighting style the best. I like to be able to attack and deal decent damage from a long range. And when I am up close, I have good defense in case things get heated.
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