Although it may go against the general characterization of the vex according to the lore, I am hoping one day to encounter a major vex opponent with a clear personality of its own. This could be the result of some major corruption severing it from the collective mind, or it could be an extremely advanced form of AI gaining sentience and developing a range of emotions. After seeing the well-written characters of Cortana, Guilty Spark, and GlaDdos in video games, I think that a self-conscious vex mind would make a fantastic raid boss. For example, it could corrupt other vex units to do its bidding, granting them better and more aggressive AI in the process. It could also fuse multiple units together to create Frankenstein - esque abominations to battle in-game. Truly, I think Bungie should capitalize on this idea for the next story arc/vex raid.