So, after a few hours:
-They've vastly improved performance and the polish on animations. Tactical battles are no longer a nightmare to play through. Frame rates are doing great.
-The stat and combat rebalance seems to be working ok, at least with single units attacking each other. However, there's been some monster rebalancing, and just throwing peasants at guys with 1 or 2 defense is no longer viable. Defense seems really important now.
-Following that, creeps are much nastier now. They go for unguarded towns like they were supposed to originally now, so all towns have to have at least 1 guy in them. There were many times I just ignored a sufficient military and blasted creeps with magic and summons. That's totally gone now, and even going full tilt on magic, you'll need foot soldiers and mooks.
-The city rebalancing is totally a step in the right direction. There are many more factors to consider now during city building and specialization. Food is very important, once again, as it seems they've toned down a lot of bonuses you get from research and such. You also get a free +prestige structure at the start of the game, which means your capital city grows fast and takes up a lot of your food supply. I haven't gotten awesome caravans rolling yet, but at three cities each with a food resource and the research, and I'm not awash in excess food anymore. So, that and the fact populations are a resource now, and there's more to consider.
However, there are a couple gaps in the system. You can build as many of most structures as you want. So, you can build 8 archivists in a city, at a cost of 5 pop a piece, if you want to. Which isn't hard, since you have hundreds of population to play with, the mats are easy and they only take up one tile. Which kind of addresses the city balance issues....but sort of not. Because now you can super-charge cities for the resources that are available. I have to spend more time with it and play a few more games....but right now I've got boatloads of excess population to use, and because of the slow rate of my research atm, the only thing I have to invest them in is.....research. So. Not really specialized. Once you get the basic necessities taken care of, it seems like you can just load up every city with extra research. (Or military, since each military unit is 1:1 population cost. So a full unit costs 9 population.)
-They've introduced some new and rather stupid bugs. Like your Zones of Control resetting after a save to something smaller than they were. So the game is continuing to advance while you have to rebuild all your shit once your ZoC regenerates to it's actual size.
-The UI got a decent face lift. I think I like it.
-Some of the customization options. like finally being able to re-design NPC hero unit cards, has been worked in.
-The spells are kind of moving in the right direction. For example, recall costs 8 mana, and returns you to your capital. Teleport costs 16 mana, and sends you to any friendly tile. So it seems like they're finally starting to get what makes for interesting balance choices where spells are concerned.
-The spells still aren't wowing me as I go through the levels, but they've really dialed back how much you get to start with so I haven't seen a lot. You have to research most spells books now, which really slows down the rate of spell acquisition. Some of the new spell book art looks pretty nice.
That's about it for now. If there's a lot more coming with 1.1, I'll possibly be recommending people revisit it. If you want to know how all this new mechanical shit is shaking out though, it's worth a look now. But Stardock being Stardock, they've introduced more frustrating problems along with all the newness.