if any Attribute fits the bill for Polymorph, Dexterity seems to be the best fit. YES, Strength can easily be a factor based on the context, and it would make sense if the spells in question increase your physical strength. However, another argument could be said for having it governed by Dexterity. I can imagine that Polymorphing on a moment's notice could require a bit of finesse. And Dexterity is often associated with finesse. I'll leave it to you guys to figure out how that might work...
stronly disagree. Dex is the least fitting attribute out of them all.
I could make a case for any single one other than Dex.
Changing your body doesnt take dexterity or finesse as you call it. Because you fundamentally change how your body works, if anything, your dexterity with your limbs is made irrelevant by the fact that you change them.
Also from a gameplay perspective, dex based trees such as Ranger and Thief benefit the least from what we know of the polymorpher tree so far.
It would make very little sense to make it scale with that attribute unless larian brings back Spears as Dex weapons, as to make the polymorpher into a dex warrior, but i still dont see how Dex fits with polymorphing.
Endurance seems to fit the best for me, having strain on your physical body.