AQ vs KK is no different than A10 or AJ vs KK. Even middling Aces like A7 or A8 aren't much worse off because of the lost straight possibilities due to two K's being taken.
I haven't looked at the numbers but I would bet that A2-A5 are better off against KK than AQ.
The numbers have arrived -- thanks to www.sliceeq.com -- and your hunch is right. After 100,000 Monte Carlo simulations, Slice declares that winning odds are as follows
KK (70.9%) vs AQsuited or AQoffsuit (29.1%)
KK (69.2%) vs A5suited or A5offsuit (30.8%)
The reason why the seemingly inferior hand of A5 does better is that it has about a 4.6% chance of making a straight. (Usually A2345, but conceivably something else) The AQ hand has only about a 2.7% chance of making a straight, because the deck is depleted of Kings, making the desired AKQJT straight hard to catch.
In general, Slice is a wonderful -- and free -- tool for testing various hand outcomes, particularly against likely ranges that an opponent might have.
NOTE: The simulation percentages above will vary slightly each time Slice goes hunting for 100,000 random hands. But the disparity between AQ and A5 generally is somewhere between 1.5 and 2 percentage points.
I haven't looked at the numbers but I would bet that A2-A5 are better off against KK than AQ.