When everything just looks like ulamog in different poses, or fodder soldiers making some sort of attack, it makes the game harder to play.
Homogenization of the art is only a problem when the direction is bad. The art had a very concise style in Khans but you could tell the cards apart very easily. Cards having the same style and looking the same are two different problems. I actually disagree with you that artists should get to add their own style into the art. It has to look similar stylistically within the same set in order to create unity. That doesn't mean cards should look the same as each other, which is a problem that BFZ has. Two cards can look like allies and not both be allies, but they are stylistically different so they don't both look like they're from the same set. This is a failure on both accounts.
In limited, you can use those late picks to grab the little ingest guys that don't do a lot else.
My problem is that it's not worth the card to set up processors in limited since most of the ingest cards are so bad and the payoff is so little. I mean, if you can get multiple exile effects in your removal then fine, but you're still so rarely able to pull off the process trigger. And even then you get what, a bounce? extra discard?
There's way too many Processors just doing incidental bonuses for the mechanic to be a focus for the Eldrazi. It doesn't feel like you're working towards something that isn't really more powerful than we normally get
without the setup. If Mind Raker just had ETB discard it would be a great common that wouldn't blow anybody's minds, but it's a processor in BFZ because... we need processors.
If it was process a couple cards, get a mind rot, then I'd start worrying about how many ways I have to get process triggers in my limited decks. As it is, you'd be lucky to exile two cards per game in BFZ draft, which means the number of processors you can play for anything outside the value of their base stats is pretty low. If it were me, all the processors would be uncommon and have stronger effects and
all the common eldrazi would have ingest.