Yeah, I've often wondered something similar myself. If valve will do anything drastic to how dota works. But I doubt they will.
Also for reference on game length, heres a graph of the lenght of my last 50 games;
[Blocked Image: https://dl.dropbox.com/u/1972432/match_minutes.png]
As you see it looks like it usually takes 45-50 minutes for each match, just like in Hon. Also, end game heroes usually move around a lot more than in the beginning. People have bought better shoes, drums, S&Y, MoM, blink dagger, force staff and all these other stuff that affects movement speed or can teleport you (BoT) places.
But yeah, It is way slower and I have heard a lot of my friends who came from HoN complain about the same thing in the beginning. Even some of the LoL players felt that it was very awkward last hitting creeps because of how slow the animation was. But it only took a few matches until it feels natural again, so just try to stick with it ![]()