Their infantry is now (properly) equipped with kite shields, which makes them more or less adequate, at least compared to what Caelum or monkeys get. Just dont send them against 2x blessed jaguars and dont expect them to kill heavy cavalry.
Bless strategy is out of question, but nature 4 seems to be a very good idea. You have no nature income nor nature mages, and your mages are just too old. Shroud of battle saint will make them last longer.
Regarding blood. Indeed, they dont have any national blood summons (why should they anyway).
But they can still have arch devils and ice devils if Mictlan/Marignon/Utgard dont fetch them all before. Archdevils can be summoned by your national mages (to fight in enemy dominion), for ice devils you will have to empower with blood (easily done anyway) your God or a Bereginya.