1. Active enough although players are split across empire and ntw its active enough with 180 player 1v1 tournies etc.
2. Yes it has to be said they still suck at this, its the buggiest game for setups and lag ive played since well forever. Example a player joins your game sometimes and the screen just freezes for 10 seconds and you cant even type in the game chat (i have an i7 btw) and 8mbit broadband.
3. Yes theres still some golden oldies around, alot have come back in anticipation for stw2. In terms of how good it is id say its the 3rd best totalwar game online, 1st shogun 2nd mtw1 3rd napoleon. The others dont even deserve a mention.
4. There are new features you may not be aware of like the multiplayer campaign 1v1 only*, so its really nice thats added but some MAJOR things are missing including the complete lack of a chat lobby, if you dont know anyone in the game currently its going to be a very lonely experience till you get your steam friends list filled out. You basically cant chat with anyone anywhere except in a game.