As an already retired player, I can still say that if Global had healthy player numbers, Expert match could have been a welcome addition. Or if we wanted to spice things up, instead of expert matching, lock the whole of UH for everyone until they do what would count as JP's expert match requirements. I feel that this would have been a more involved way to create an actual gate for the more dedicated and talented to achieve, and would leave casuals and the lazy (and perma-bad players like me) to stay on XH and either try to go up or stay comfortably in that difficulty for the life of the game.
This method would keep lower tier players from becoming burdens on UH content they actually cannot do but are allowed to try, while keeping experts from carrying groups of less prepared players simply because they wouldn't willingly drop a difficulty tier and miss on the higher mode's rewards, unless doing it to help friends to gear up. In other words, Sega could have used the difficulty tiers as actual gates to work for, instead of tossing everyone onto the highest difficulty and throwing the burden to carry onto the better prepared players.
BUT again, this would only work if the game has enough numbers, which I really doubt it has. Maybe this could be added to NG as a way to nudge players into getting better, or to choose what difficulty they want to stay at. Because on the current system, even though I did several UH 12man urgents and I feel I have contributed to the overall goal, I still felt that it wasn't the tier I wanted to be at. But with no real clear division, it was the tier everyone seems forced to go to.