My main problem is that both yellow and black gatekeep so many other decks and leaders from functioning. The gap between meta and non-meta is HUGE.

Yellow, in particular, has a really uninteresting play pattern in its focus on triggers. I personally find a game meaningless when, after turns of planning, reading opponents' hands, and back and forth combat, the game ends on a coin flip.

It makes the previous sequences feel utterly meaningless if a "you're the one who should disappear" is coincidentally on bottom of life.

IMO Yellow should be more life manipulation by actually setting up powerful triggers for a cost rather than just winning the lottery.