That's another extreme annoyance with this event. Elite pays out 50k unit xp, but you can't realistically bring a unit in there to be carried. So all of that is wasted.
I'm actually seriously thinking of dropping down to PRO difficulty and auto'ing for rank xp after reaching the 11k shards for all the base gear. If not, I think I'd rather go back to TM farming, which is generally the very last thing I want to be doing in this game.
I like the difficulty of the event, but I'm sad that my A-team (recently made), is just severely underleveled and has no chance currently. 4k per unit doesn't sound like a lot, but as often as we need to run this event? Its working wonders. I enjoy Pro, even with 3 scrubs I can autoattack on accident instead of repeat the boss and still live/win, I wager I couldn't on Elite. I've gained 3 rank ups just farming Pro (50-52) since this event started, no lapis refills, and only two bottles saved in the mail.
edit, While I have several lightning friends, none have broken into the 6 star territory yet. I'm only 4250~ / 8000 myself. Pro lets me just setup the first round, repeat x4 (add an esper summon to the boss), than repeat again.