They should really remove the exp cap based on time. In fact they should remove the individual exp caps too(like caps from exp gained on damage done, healing, etc).
Though the time cap is what really screws campaign battles when it's crowded. You could do so much in 1 min but can only gain 90ish exp only.
Has anyone found out if rdm/sch uses composurer while AoE refresh/stoneskin/etc. does it lengthen times on other party member or still just the caster?