Yes, once I heard that they're using unity for Pantheon, that gave me a little PTSD. I don't know much about it, perhaps it can handle it fine? But I haven't seen a MMO with unity.
I'm happy with 24 man capped raids. I think they work well. It's enough players to be part of a big team, but small enough to tune encounters, make every member matter and deal with hardware limitations.
As I've been reading more about what info is available with classes for Pantheon, I haven't discovered too much about class synergy. It was a long time ago, but with VG, I'm pretty sure some classes debuffed mobs with weaknesses for brief periods in their rotations and if you as another class noticed you could use certain abilities to take advantage of that. I haven't noticed very much of that has made it through to Pantheon as of now from what I can see. Hopefully a little more of this goes through. It's fun, rewarding & increases the skill cap.