What I wish SE would do, is reduce the severe penalties for grouping up.
Seriously, there is something wrong when, in an MMORPG, I find I get better XP solo (far, far better XP) than in a group until you get to Apex.
They kinda-sorta did that in Adoulin Dungeons, but it's ONLY in Adoulin Dungeons. Everywhere else in the world, you are strongly discouraged from grouping up with a friend. Trusts are better than human players because Trusts don't eat 30% of your XP gains.
I've been wanting to XP with a couple people I know, but the penalties are just too harsh, and I find myself saying "screw it, I get better XP solo".
The only place where XP really matters these days, is at Apex Mobs and those are usually only done with a full group of 119 players. Therefore, if we reduce the penalty Pre-99 and <6 player groups, we wouldn't be hurting anything, and we would encourage friends to group up again.