+ 10000000000
Let me explain this once again: we are not "backward compatibility killer maniacs" :) We prefer to keep backward compatibility whenever is possible, but we don't put it as a top priority: if we find room to improve, we do it.
but, since we take responsibility for all the packages loaded in what we call "pharo", we rather prefer not to have duplicates, so we achieve one of our goal (cleanness) while also focussing out effort.
I'm sorry if that annoys some of you time to time, but that's the way to improve: to change.
Also... I think you are overreacting, in pharo 2.0 we just introduced three big changes (visible to users): FS, SystemAnnouncer (who has, btw, same API than old SystemChangeNotifier) and Nautilus... that's all. All the other is infrastructure and shouldn't be a problem for anyone.