Personally I like the idea of him having a wolf shapeshift, since his fellow elvhen god Flemythal has a High Dragon form. But that's as far as it goes.
On wolves; I'm not really big on when people really really overstate the wolfishness of Solas/Fen'Harel, particularly in the context of Arlathan. Like, within the context of iconography, or quaint Dalish lore - that's fine, stories exaggerate, and it's a big part of symbolism surrounding Fen'Harel. But I imagine the reality of the Elvhen empire to be different from those stories, and I imagine it refers more to his personality, his intentions and actions, his modus operandi, his position on the edge of the pantheon, etc.
Particularly, I've read fanfic before which refers to 'The Beast Within' or 'The Wolf Inside' or something overly dramatic and just.... no. Especially in a sexual context, I can't be doing with it (it's like a male, lupine version of 'inner goddess', yuck). Too much just reminds me of the amazon reviews of the three wolves t-shirt. Too cringeworthy for my taste.
Oh yeah, you are right, it does go too far sometimes. I do like the symbolism in general...but it is just supposed to be symbolism I think. Maybe the fandom has a tendency to over think it too much, or take it a little too literal sometimes? It's a fantasy game with Magic. But I remember this used to really give me headaches with the whole Anders vs Justice vs Vengeance debates sometimes. I'm like, gah, it's a metaphor/allegory!
So I guess the questions of whether he is really Fen'Harel, or an elf possessed by him, or whether Fen'Harel was actually once a wolf or a spirit of a wolf...is sort of irrelevant to me. I don't think it changes the narrative all that much, and should probably be left up to interpretation.