I will be honest, I haven't played much with the polymorph skills compared to summoning although I couldn't help to think that the skills just aren't very "innovative" and don't seem all too useful to be honest.
"Bull Horns" is nearly a direct copy of "Battering Ram". So if you have a warrior character with polymorphing, you end up with 2 "charge forward" skills which is kinda silly.
Chameleon Cloak is simply stupid when "Walk in Shadows" needs 1 source point. Plus where's the originality gone...
"Tentacle Lash" is awesome since there's no other skill like it and makes the enemies run away which can waste their AP.
"Heart of Steel" is the same as "Fortify" although "Heart of Steel" has this regeneration to it so it's slightly better I guess.
Finally I don't even know why "Chicken Claw" is in the game but I guess it's useful cause it ignores any sort of armour (at least at the moment). It also makes the enemies run away similarly to how "Tentacle Lash" does.
I'm sure we all thought about some of this but everyone had been concentrating on totems a lot recently so I just wanted to point these things out. No I don't have any better ideas at the moment, mainly cause I can't be bothered to think of any but we can use each other's suggestions to come up with new ideas.