it was bullshit for people with ALT item bindings
This exactly. That change should have been a checkbox in the options in the first place.
Re: Bindings
I used to ALT bind but I've since switched to Mouse4/Space/VZXC.
I encourage people to give it a few games, because it's a noticeable improvement in speed once you get used to it (which I still am not, entirely. I would like to rebind V to something further away from ZXC).
I'm also using quick cast now and haven't felt a need to rebind mid-game. Certain heroes would demand it no doubt, just not the ones I play.
(Mouse4, Space and V are also quick cast)
Over the first few months I started playing Dota, I tried different item bindings including ZXCVBN, 123456, and even the awful default numpad bindings. I had even tried stuff like WASD camera for like, two games and hated it. None quite stuck with me like Alt+QWEASD. At worst I accidentally ping while playing Tinker, but I rarely mistakes that are due to my fingers not moving properly on the keys. Mouse4 isn't open to me as I use that for voice chat, neither is space as that is for jumping to an alert on the map. Number keys is bad because you need those for control groups.
As for other options, for the most part no item bindings are better than others, and all the regen change did was fuck over people with Alt, and people that were used to the old way for years and years, with no real reason to change it.
Regarding quick cast, I have tried it and never liked it. I have to have the feedback from the clicks on my spells, not having it really throws me off. On top of that, I like to be able to see AoEs and use the range finder, all of which quick cast takes away.