[Omnirizon]

I can't entirely agree with the OP.

certainly, there are some damned useless summons.
but as vtb notes: national summonable sacreds can be OK sometimes.

and spells that summon lots of pretty good troops at reasonable prices are good, like the higher level, often national, summons. spells where you get 20ish units around 30ish gems; units with over 20 HP, and str and prot over 15. But I don't know, I'm only in my 2nd MP game, so maybe these are actually useless. They look pretty tasty to me though.