When it comes to tooltips, HoN makes a good example. They used to have massive tooltips with almost every bit of information you could think of, which was actually fairly useful at times. However it turned out a lot of people didn't like them, and $2 changed them to something similar to what Dota 2 has now and everyone loved them. They did leave an option for enabling the old tooltips, but they were more or less broken for new heroes.
But I don't really care about tooltips in Dota 2, there's little to no things I don't remember and the only things I sometimes check are the level scaling values which are displayed anyway. They should just make the in-game hero database better, and maybe sometime in the future when they have time make advanced tooltips available.