My perspective is this:
In some cases, it does make sense to allow the target of a Force power to defend himself against the use of that power. Influence/Mind Trick type stuff is a good place to add that.
The Move power, however, is not a good place to use it, unless the defender is also using the Force (see Anakin and Obi-Wan trying to Force Push each other during their duel in Ep. III). If a Force-user uses the Move power against Boba Fett to hurl crates at him, as was mentioned previously, then no, I don't think Boba Fett gets a defense against that other than dodging out of the way of the crates being hurled at him. If a Force user wants to push Boba Fett off a cliff, then Boba Fett has no defense against the push, though he might react to the fall afterward.
But I would argue that the discussion of adding defenses against Force powers is akin to treating the symptom rather than the disease. The powers themselves are the issue; they are simply too strong. The ability to Force-move a Bantha should not be in this game at all, period. This game is not about high-end Force-users; powers of that magnitude should, in my opinion, be reserved for the Force and DEstiny book and nowhere else. At the time of the Galactic Civil War there are probably two individuals in the galaxy who are THAT strong in the Force, and they are Yoda and the Emperor. I don't even think Darth Vader can do that kind of thing.
If it were up to me, I would tear the entire Move table out and start over, making is substantially weaker as befits the Edge of the Empire setting and power level. The MOST I would allow it to do would be to let a character move, say, a backpack-sized object at long range, and only moderate speed, and even that is a rare feat for a Force user.
It's a conservative stance, but I think treating the Force conservatively in EotE is the right approach. And if the Force powers were tamped down to a more appropriate low power level, the there would not be this great need for defenses against them (though it would still be appropriate in some cases).