I like Sandman's suggestions about reworking pretenders and fortresses, but unfortunately that quite a lot of work...
Differentiating the pretenders from each other is, IMO, one of the things that would help the game a lot. The descriptions are wonderful, but unfortunately all pretenders don't stand up to it.
About holy spells:
Some national/theme-spesific holy spells would really do wonders on ceratin occassions. Think Iron Faith Ulm, as an example. "By the faith in iron shall the people of Ulm survive"... Holy 3 Legions of Steel would be the physical manifestation of such a spell.
Other nice spells that would be nice to see as holy include some summons (esp. those of Tien Chi), Magic Duel ( Don't you dare to expect The Inqusition!
), Holy Pyre, Banish Demon (with 5+ priest requirement), even blindness and/or curse for some nations.