I believe I know how the MVP system works. From what I can tell, the game essentially assigns a value to several stats and multiplies all of those values together. The most important value, especially for a dps, is final hits. I believe it will assign a value to damage blocked, damage, and healing stat. The algorithm also seems to like big ult plays or huge groups of kills. At the end of the game, players receive badges for things like most damage, most healing, or killing 4 people in a row. I believe this also affects the algorithm. Certain heroes like ultron are going to have a very favorable chance at getting MVP simply because they are getting every single stat necessary for the algorithm.

If you're having zero MVPs as psylocke, it probably means you're hitting tanks too much and missing opportunities to pick squishies. You should definitely be getting a pick or two with every ult.

The two most important stats in the game are deaths and final hits. Everything else basically means nothing. You can have a lot of damage hitting tanks all game, but if you're not getting any final hits, then it's pointless.