How do we know Solas will be the antagonist? We were given the impression that "DA3" was going to be about the Mage-Templar War, but that was hardly the case.
I'd be happier if we didn't get some god-given ability. I mean, once is enough. I'd be OK if we got small ones like in the Warden's Keep DLC, or the Hawke-specific bonuses and the Dog summon. Oh, and the Inquisitor-only bonuses.
Also, I think the ability to turn into a dragon would just be too silly. I can see how that might come about, being set in Tevinter (assuming it is), but actually implementing it into the game... Either it would have to be a small dragon, or BioWare gives us a poorly integrated side quest or mini-game. Now, I could see potential in riding a dragon, but probably only in a cutscene (which would be pretty cool all the same).
I suppose a mage PC could get a dragon summoning spell, or a powerful scroll like the Litany of Adralla, for rogues and warriors (or all 3 classes). Maybe the PC has to enter the Fade to obtain it. That'd be better than actually turning into a dragon. Does DA have summoning spells?
If Solas is the antagonist, I would hope that there'd be a better way to defeat him, than with a powerful ability to match him. Like, say, powerful Tevinter mages worked with the PC to weaken Solas with powerful spells.