It's an ok game, haven't played it after the official release, but I played a bit during the early beta, and then again during the pre-launch beta which had a lot of changes and fixes.
It's hard for Valve to please everyone though. If they really go forth and make it a proper CS 2.0, then there's gonna be people crying all over how "this is too different and not CS, CoD ruined this!". However, keeping too much of the same golden formula will instead have people whining "It's the same game, graphics sux".
Some good points about the game though is that it's cheap, and finally an official release for current-gen consoles. They've fixed the surround sound engine, added options that affect your PoV depending on if you play in your couch or in front of your PC and it's fully playable with controllers.
Minor visual changes are for instance that they've removed character selection, and instead have each team feature randomly different-looking characters from the same faction. So instead of having a rag-tag group of american special forces fighting finnish terrorist along with some guys from italy somewhere in the middle east. You'll now have more local factions fighting in slightly more native environments. They've also added 4 more factions to each team.
Weapons have been balanced and tweaked, like the removal of silenced weapons for the CTs, while also completely replacing other weapons, like the MP5->MP7. There's also a new molotov cocktail grenade that you can buy, and a diversion grenade that will make gun sounds and confuse the enemy (don't remember if they kept or removed it though).
Gun-game is also an official game-mode with custom maps. When playing Classic game-mode you can choose between Casual or Pro. Pro plays more like 1.6, while Casual for instance removes friendly fire and friendly collision (if anyone remembers how awful it can be to exit spawn with the jerky collision detection getting you stuck into other team mates and slowing you down). There's also a third game-mode that has shorter rounds and smaller maps, where you cycle through different weapons each turn depending on your performance in the last one. It's a bit difficult to understand, but might be taht they've changed it since I played it in the early beta.
Oh and there's obviously the tight integration with Steamworks, with achievements, avatars and nicknames, leaderboards and all that. I know a lot of these features were added to CSS in the 2010 (or was it 2011?) update, but this time it's there from the start and built around it.
That's all I can remember right now off the top of my head.