Providing the core conquest game is still there - which it is. Why can't they use the DLC to develop additional game modes to branch the game out ?
Part of me thinks that trying to do it with a small, 4-map DLC is doing things by halves. If they want a fast-paced, small area shooter then grand, I've no problems with that. But would they be better focussing on a larger expansion-sized DLC or even a separate game for that?
Trying to shoehorn it into a game with a totally different style could cause a lot of clashes: because it's a 16-player DLC on a game which is normally 32+ on PC you're giving server admins a choice between cutting all of their maps down to 16 or just running the DLC. Given that the premise of the game is larger maps, more players plus vehicles I doubt many people will want to cut their 32+ server full of regulars down to 16 players. B2K was fine because the maps could slot right into the server without any changes, but CQ maps won't be able to do that without having to kick half of the players each time a CQ map comes around. Arbitrary kickings are a great way to drive your regulars away. The only alternative is to run a 16 player server mainly for the DLC. Who wants to pay for an additional server just for 4 maps?
The other thing I'm mildly confused about is what they're doing with the classes. What the heck is Recon going to do? Quickscoping with bolt-action sniper rifles in buildings is dangerous because you get one shot and then you either have to sit and reload or switch to your pistol, whereas your shogtun/LMG/AR-wielding opponent will happily be spamming away. The semi-auto rifles could be handy with a holo scope or iron sights, but why use that when you could use the shotgun or an SMG which are actually decent for hip shooting? The MAV will be no good in those small buildings. The SOFLAM is pointless on an infantry map. It sounds like they're messing with the spawning system so the spawn beacon may be useless too. The only reason to go Recon at this point is the TUGS, and given the loud beeping it makes and the amount of explosives going around it probably won't last long.
Compare that to the Medic: You can have a fully tooled up assault rifle, shotgun or SMG which is great for close combat, plus the M320 with grenades or buckshot, plus the defib for reviving your mates.
Unlesss they've been keeping some major changes up their sleeves it sounds like shoehorning CS/UT style gameplay into BF will first of all grind with the already established server setups instead of slotting right in, and it'll also push people away from the already neglected Recon into other classes.
I'm just not convinced that trying to cram a small, 4-map CS/UT style expansion into BF3 is going to be smooth and that it won't leave a lot of the stuff originally developed for BF3 (like the Recon class, Engi's mines and repair tool, Support mortar, etc.) sitting on the shelf and not being used. If they wanted close quarter stuff they should have gone for a full blown expansion and done it thoroughly, designed for CQ right from the beginning instead of trying to tack it on the end of a game designed for a different style of gameplay.