Huh.
Last night, I came back for the first time since before the new rewards system (about a month and a half to two months). As such, I was Level 1 AND I decided to play Antag with Kwana who I had just received as a mission drop.
So Level 1 with an unfamiliar character on a game that I hadn't played in two months. My opponents were a Level 3 Alicia, a Level 46 Harec, a Level 70-something Hans, and a unknown Level Shae on the free map.
Beat them before they got past the second part.
One of the things that stood out was, when the gas was exploding, Hans, Shae, and Harec (the one that I had been chasing) decided to stop and beat the crap out of me while their shuttle was out of Aleph for the second time. They won....then died.
I mention all this because, given the examples above, they should have wiped the floor with me if Level was the only factor as some of the posts are suggesting. Instead I overcame a massive disadvantage to win. To me, this indicates that a lot of people are using the level difference as an excuse for (and there's no kind way to say this) being terrible at the game.
Instead of playing defensively when Aleph is out, you charge forward.
Instead of using your skills and tactics, you charge forward.
Your teammates need help, you ignore them.
Somebody is carrying the McGuffin, you go off to do your own thing.
And I know it's possible to use tactics. Before the hiatus, I played Antag (Alicia, I believe) against a party where two out of four of the raiders quit before the end of the first stage (It was the one where you save Old Protector). The other two got it together and proceeded to hand me my ass for pretty much the entire stage. I only won by a fluke and, really, I should have lost.
Similarly, as a raider, if I see one of my team go down, I will move to cover them instead of just doing my own thing. If I have to intercept the antagonist and a bunch of AI so my teammate can get the McGuffin to where it needs to go, then I throw myself on that figurative grenade. Basic tactics tend to put me on the winning team a lot. (Not always in either case but I believe that I have more wins than losses.)
And that is probably the bigger issue than the MMR. If I can win a match with the aforementioned disadvantages, then MMR isn't really the problem.
Now, I understand a lot of you don't want to play PVP (Level9Drow, looking at you) and that's fair. Unfortunately, there is no real way to create a PVE/PVP division without killing the game's online altogether. SWTOR, which has a much larger playerbase, decided to merge the PVP and PVE servers last year and just allow people to switch instances between the two. Result: The PVP instances were abandoned and the remaining PVP playerbase left. (Some still hang out in the matches or on Ilum but PVP, as an open world experience is pretty much done.) Maybe, if this game were Halo or Gears of War, it could make that division due to the large fanbase those two games have. Raiders simply doesn't have the playerbase to get away with that without the online crashing and burning.
As an aside, I wouldn't mind seeing minor XP rewards for offline. (Say, 100 XP for easy, 400 for medium, 900 for hard, 1600 for very hard.) Have these rewards as a reward for every time you beat it with a unique character which would provide an XP cap but a generous one that encourages the accquisition of new characters.
In the end though, this game (and the industry) is largely geared towards multiplayer. There's not really a whole lot of ways around that which do not end in "We're releasing the last campaign and shutting the servers down."