The only ones I've found "too easy" so far are the S-license tests (besides S8, because I just can't get used to having the stupid aids on). So far I've fully-golded B, and have like 2 left on A (can't get the stupid slalom on gold, I guess I don't know the technique). Everything else is a mixture of silver and gold, but a few of the silvers were even difficult to attain, and the gold times are another second off of the silver time. I intend to finish up S with all golds, but then I'll leave the rest of the licenses silver for a while, as I need to get on with the meat of the game.
So no, I don't think they're too easy as a whole, as you still have to work fairly hard to get gold in some of them.
Or maybe I just suck