As far as I know, peryite is acknowledged as a prince, just the weakest one. Malacath is technically not a Daedra at all, but this fits his sphere perfectly, being the patron of pariahs and outcasts.
Hircine is in no way weak, he simply has a very specific sphere, the Hunt. While he meddles with mortals quite a lot, he always strives to give them a chance, otherwise where's the fun right? If the prey can easily elude it's hunter or the hunter can easily catch his prey, what's the point? This may lead to other Princes seeing Hircine as weak, Molag Bal for example would not give mortals a fighting chance because it doesn't fit in his sphere of domination, so Hircine may seem weak to Bal. Then again, everyone seems weak to Molag Bal, that's what he's all about.
It depends on the source really, some places have named Peryite as a prince, while others have said hes just a really powerful daedra that the other princes dont really consider a prince.
Also, Meredia, Sheogorath, and Dagon, aren't real Deadra either, but they are considered princes. With Meredia being a Magna Ge, Sheogorath being a fragment of Lorkhan, and Dagon originally being a leaper demon.
But if I had to pick one Daedra as the strongest, I would have to choose Dagon. Dagon has been through so much more, and survived, then any other Daedric Prince. Dagon, who overthrew the Dreugh empire, smashed Molag bal's coldharbor into bits, and freed the world.
Edited by sajuukkhar9000, 24 January 2013 - 07:20 PM.