Interesting question, Ted. At my Dojo, Ki testing is certainly covered - we do a certain amount every day after hitori-waza. Personally, I think it's not excessive at all; Ki is the defining difference between Aikido and other MA - at my low level, I'm learning to 'move with ki' while performing technique. Even I can see - and feel - the difference between (for example) doing Ikkyo (Katate-tori) just using my arms and back, and with using one-point.
As far as testing goes, I think it's crucial, not only as an evaluation, but as a teaching tool, which is the greatest value of any good test.
Hope my humble opinion helps.