I'll wait to give more comments until I actually get to see the full index rules, but so far 4e isn't looking worth it to me. Thankfully I have friends who still want to play 3e. Kroak and the Carnosaur, my two favorite models, are basically useless with those point costs. Everything's going up in lethality, gameplay seems to be all about massive "wombo-combos" and chaining reactions and trap card-esque strategies on your opponent and wiping them out early, or getting wiped out yourself.
Definitely not a fan of control score, and that so many units have abilities that raise or lower it. Just another annoying stat to keep track of and constantly be adding and subtracting from. I don't like the way it sounds like it will play where one player goes "I have more guys over here, so I'm winning" Then you say "Oh, but my guys have a banner that says I'm winning!" Then they go "Oh, but I can use this ability where my hero yells at you menacingly so I'm winning!" "Oh, but my hero has an aura of awesomeness that negates that so I'm winning!"
Very "gamey," as Canas put it. It will be fun for the super-strategists to be able to laugh at you and pat themselves on the back because they managed to win in points because they had better control score even though you managed to outmaneuver or outfight them, but it doesn't sound fun at all for any sort of casual play.
I'm not a "doomsayer" when it comes to new things, but I'm also definitely not one of those people who's always excited for new thing because new thing. So far, new thing looks a bit rubbish and I'm definitely not very interested in it. Which is a bit saddening because some of the basic concepts for 4e were looking interesting. But everything just looks so lackluster and they've massively nerfed so many things for no reason.
I guess with each new edition there's a specific idea GW has in mind as the "right way" to play. Having come in at the start of 2e and seen the transition to 3e and now 4e, as well as going through a couple 40k edition changes now, I personally always have a hard time figuring out the "right way" GW wants me to play my favorite factions. And when I do figure it out (or someone smarter explains it to me, lol!), it's usually not the way I want to play