Lore-wise, I do still miss Flash.

It made perfect sense for a Gladiator, since the point of gladiatorial matches is to be entertaining and, well, flashy. So a move that made aether emit a bright (but relatively harmless) light at the tip of your sword to catch everyone's attention is exactly the sort of thing a gladiator would come up with, and spread through the other gladiators.

Of course, I also understood the game-mechanical complaints against it. But Total Eclipse/Prominence doesn't really have that perfect backstory justification.