Since I made my first reply in this thread about going to a shorter stem, I just a few days ago put the 100 mm stem back on. Other than some minor things that might just be adjustment of where the STI's sit since I extended the reach, I haven't seen that it really makes a big difference one way or the other.
Certainly none of the big scary claims you see about shortening the stem elsewhere ever came to being. It was mainly a matter of just getting use to it like any other thing you might change up on the bike.
So if this thread is still about experimentation, the by all means I encourage one to experiment. And don't let the results of only one short ride after changing the stem keep you from doing additional rides just to see if it's more you needing some retraining than the actual change.