My primary concerns/thoughts about a "duo" category, for videos that consist of only 2-4 people:
How many of them are there really? (now, there could be alot; I don't have a filter or anything to look it up immediately). If there's only a few a year, I don't see the point in seperating them from the larger category (I can only even think of a few that came out).
Also, I would like to point out that a large MEP is more likely to be jack-of-all-trades master-of-none genre wise, compared to a smaller one which can look much more coherent. I think a video that say, only has two to three editors on it stands a much better chance in the normal categories.
So if they can possibly stand out more in the regular categories, and there's not that many of them, is there a necessity to seperate them?
Personally though, I really don't care how many people worked on a video together, and I don't think that just because someone got along with someone else well enough to make something decent with each other holds much merit by itself. So, really, I would be completely fine with abolishing the MEP category altogether