I found that students starting out in a 172 had more trouble transitioning to the 150, than vice versa. They tended to overcontrol or let the 150 wander too much. The 172 is (IMHO) too stable to be a good initial trainer.
While you're probably right re flying a 152 if one hasn't done so before, the second part of your argument doesn't really hold water. It's about the same as saying driving lessons should be done in some clapped-out 50s vehicle with no power steering and dodgy brakes, just because you 'learn more'. You don't.
In any case, every a/c type is different and has it's own idiosyncrasies. As other have said, if you fly a heavier type for a while, a 172 feels, well, almost ike a 152
