Wallowing around 2100-2200 mmr because I like to play suicide bomber means that I don't mind taking on higher MMR players but when my team consists of lower MMR's and me it's a greater challenge because they're new and teamwork is new to them etc etc etc. When going against one of the best players I know of, against me and five other players, three of whom are lamenting that they are new to siege and so on, and one of them doesn't even know how to use the autotarget in Rocketeer, it's not that fun. When it's me and a team of players who are compatent going against some of the best players out there, well, to me that is fun, even if I get crushed.
Teams get stacked fast, my teammates get crushed, start lamenting, and then rage quit. There's little to no incentive to wait for the next match to let matchmaking balance out the teams. I don't mind taking a pounding so I'll stay to the end, but getting caught in a match filled with low and high players makes things a little more frustrating. The higher players eradicate everyone without mercy and the lower players don't have any fun, nor do they get a chance to learn much, because they pretty much die right away.
Also, ping. My ping is horrific, sporadic, unpredicatable. Going against people with 24 ping while I'm cruising at 84-120 makes the whole idea of MMR moot. They see me an instant before I see them. If Matchmaker balanced between MMR and spread out ping so that players with high ping were split up between teams, that'd be awesome too.
Back in the day when you could see people's levels (1-30), that kinda gave people an idea what they're were up against. You could tell which high level player was being a turd and camping lowbie matches. Now it's not obvious. Granted, smurf accounts would still prevent people from seeing what other players are really capable of until the game starts- but I think if more high mmr player found matches quickly the amount of smurf accounts would drop dramatically and used only by turds who want to camp lowbies.
The 3 star rating for servers isn't very telling, honestly. I can't tell if the three stars means games are gonna be too low, or too high. Being high-mid mmr or whatever, it usually safe to say that it means they're gonna be low, but I bet it can be confusing for other players. Sometimes the lower players do wander into higher matches because of them.
/rant Also there's no penalty for leaving matches early (especially leaving near the end, dumping some poor soul into a losing match)- and while that is another topic I'd rather see that dealt with than matchmaking itself. /endrant