I think it makes sense to say that these guys are the 5 most consistent players. If your criteria for Marvel deity status is simply those who are on the top of the mountain, then youd be correct in calling these guys the Marvel gods. Of course some would argue that its a defeatist attitude, but it really just depends on your definition of Marvel god.
However, I will say that I dont think the skill gap that separates the top from the rest in UMvC3 is as wide as it was in MvC2. The gods of UMvC3 are currently the best, but the gods in MvC2 were far and away the best. Whats interesting is that if you watch the old EVO 2002 MvC2 top 8 footage, when the only gods were Justin and Rowtron, you can see that they were also far and away the best at the time. Was this due to the nature of the game? The nature of the scene? You could say the advent of the internet and YouTube has played a major role in narrowing that far and away skill gap. But then again, MvC2 footage had been circulating well into 2005-2006 while that gap still existed all the way to 2010. Its difficult to say. You could probably write another full-bodied article exploring this. (and by You I mean Viscant)
Again, its about your definition. If your criteria for Marvel godhood is to be far and away better than the rest, then maybe the top 5 arent as godly as we make them out to be. There are just too many good players on the cusp who have proven they have the potential to be the best.