My major gripes with the MP are:
1) The two piece. Damn, why did they re-introduce this into the game? You can be in the middle of a shotgun fight and then, bam, you get hit with an elbow and you're practically statuesque for an easy kill. If you haven't experienced somebody who is pretty efficient with it yet, then trust me; you don't want to. It's a game breaker.
2) Lack of maps. 8, 4+4, 8 (+2), say it however you like. The fact that they shipped this game with 4 maps for the majority of gametypes is nothing less than a disaster. What were they thinking? Gears 3 had a decent amount of maps on launch, and Gears 2 had a decent number + the flashback maps on launch. I'm bored already of the multiplayer because I'm sick of playing the same maps over and over. Yes I know free maps are coming but if I've just shelled out full price for this game, I don't want to be bored just after a day.
It feels like a Gears at it's core, or at least what Gears has become as the franchise evolved, but I can't help but feel short changed by the lack of content. One of my favourite weapons, the classic HB? DLC. Double XP? DLC. A majority of the character skins? DLC. A majority of the weapon skins? MSP.
On the plus side, it's nice to be reminded of what Gears can play like on a low-latency server, them dedis are one of the few reasons I keep going back for more.