Basically, my feelings about Retro including a deathmatch mode in Prime 2 are that Retro is making a mistake this time that they were smart enough to avoid the last time around.
See, when Prime 1 was first revealed to take place in first person, most fans freaked out. "Freaked out" is an understatement. It was more like "Oh no Retro is raping our beloved franchise! FPS? WTF!?! Burn in hell, Retro! Burn in heeeeellllllll!". All the Metroid fans KNEW Prime was going to suck. They KNEW that Metroid SHOULD have been a third-person action adventure. There was no way they could capture the "Metroid feel" in first-person, right?
Retro was smart to ignore the fans on that one. Instead of going with the potentially hazardous third-person shooter route, they went with what they knew worked. Now, they're adding a superfluous deathmatch mode because the fans asked for it, even though Retro probably knows it's not a good idea.
Am I saying developers should ignore gamer feedback? Absolutely not. But they should be smart enough to know when NOT to fulfill a request, when they know the request is unfeasible. They're going to get MORE complaints for the weak multiplayer mode than if they had just left it out.
It reminds of how Rare added pointless multiplayer modes to several N64 games just for the sake of having a multiplayer mode. JFG, DK64, Banjo-Tooie...
Before anyone calls me a hypocrite because I act like I know the multiplayer mode wont be anything special, I would like to point out the the E3 impressions were so-so, so it's not like I'm basing my opinion on nothing. I suppose anything could happen by the time the final product launches, but I'm not getting my hopes up.
The bottom line is, they're wasting time on a useless multiplayer mode that would be better spent on making the one player game more awesome.