[Endoperez]

Well, considering that the in-game wishes one is most probably going to try will be 'gems', 'gold' or 'magic'. The ones trying it out for the first time won't know just *how* the Wish will carry that out. In the case of "magic" (I think that should give the same as "magic power" if it already doesn't, for the reason FrankTrollman listed above), the surprise will be quite positive, I think. And as Doom Horrors will be unique in DomIII, they will be less of a problem as well.

Wishing for at least some spells should also work. I'm mainly thinking of the high-level summons, the ones that give you uniques. Newbies might not now the creature types of the summonable creatures, but they can find the spells from the manual.