You... you really think feinting is the problem? Or do you think unbalanced tag actually prevents feinting? Both? [Surprise: Both are wrong]
Unbalanced tag would really just cause a huge additional stun to the pike users after you block them. They wouldn't be able to block your return swing. Pretty easy to see the problem there. You want pikemen to not be able to defend themselves, again.
There's already a pretty long wait between pokes, and I assure you, I don't want pikemen to be unable to defend themselves (Especially when I am one, after all.)
However, it's a 300 length weapon, and it should feel like a 300 length weapon. I think that by either giving it unbalenced and adding say, +2 damage or by keeping it as is and lowering the damage would both work, depending on how the devs would want the pike to fit in the Metagame. As it is right now, Cav stay away from me, and I tend to get most of my kills via support with a pike, and giving it +2 damage/Unbalanced would reinforce that infantry support role while still being one of the best deterrants to cav around.
IMO, the strength of the pike isn't in dehorsing cav, it's in keeping cav away from the line to start with, what cav outside of stupid ones would charge an aware pikeman, after all?