> Why don't enemies get painted as red diamonds on my HUD when I see them?
I agree with KEVMAN68, it shouldn't be too easy. You could argue that you shouldn't see them when your ghosts does either, but i think it's reasonable for the gameplay.
Alternatively your temmates/ghosts could shout "Enemy on roof, north east!" or something, that might be cool?
One thing i miss is to be able to swap weapons with your ghosts, if i for example should wan't to borrow the sniper-rifle or something. Or like i recall in the first GR, you could shift player, f.ex become the sniper or the support.