I like aether and especially mindgates
It is always fun to piss of enemies by drawing four of their best cards while they draw only 1. You can focus on defending and let your enemy give you all the attacking power you need.
I don't know what that "War" thing was but in aethers pages mindgate was claimed to be useless... I disagree. If you draw a mindgate early in the game you will likely get more pillars than enemy has and be able to use more of their cards than they can.
The problem with Mindgate in the War Meta is that everyone primarily uses pendulums to run most of their decks.
This means that unless you manage to guess the correct mark they will use, you will not be able to play all their cards anyways.
The solution would be to bring quantum pillars, but this results in too much of a vault investment to put together a deck that's not necessarily superior to other decks.
It's a very good cards if you have the room to build a good deck around, but in War it's simply not worth it.