Having to learn tread switching early on would have put me off the game. It's kind of tedious and there are more important things to learn.
I seriously doubt that given the other tedious stuff in Dota that's there right on the surface.
Why do the creeps go automatically at the same time?
Why does stacking camps work the way it does?
Why can't I just autoattack the creep wave instead of waiting and last hitting it, shouldn't we just attack the bad guys to win?
Why don't I just get the items that give me more damage?
Why shouldn't I start with boots and go fast?
Honestly if Tread switching puts people off of Dota somehow, then this probably isn't the game for them.