My impression of 8th is as such.
7th died out because of a two or three armies, but primarily Daemons, dominating the crap out of the game. Since the Daemon book release I noticed player attendance at events and play nights decrease dramatically until nobody showed up but the VC and Daemon players. Literally the last two players that kept showing up were playing VC and Daemons. Everyone else quit.
As such, there's a glut of players who quite fantasy 7th. For many who played Daemons, Vampire Counts, and to a lesser extent Dark Elves, the 8th Edition rules meant they were no longer so dramatically more powerful than everyone else, and many of them stopped playing as well.
However, with 8th edition what I've seen a lot more of is newer players more than anything, and people who quit playing during 7th because of Daemons.
The current rules do have their issues to be sure, especially with magic uber spells, however I think the game is much more intuitive, balanced, and flexible than it was in 7th, and a lot less fiddly over tiny little things. There's no longer One or Two armies to "rule them all", and the game has shifted a little bit away from the all heavy cavalry armies of 7th. Infantry dominate the game, units like Chaos Warriors have become much more useful and a lot scarier, and the game just looks more visually impressive (to me at least).