Yes I agree with you, Praetorium is more interesting, more difficult to rush (as far as i know) so it should be more rewardable. Moreover it's the final dungeon ...
120 philo instead of 100 can be a good compromise ? ^^

Personnally, I'm sick of castrum because of people mood ... They are always upset to lose 1 minutes because a new guy aggro something...
Praetorium is more linear if I remember well so situation like that will occurs less often (I hope).