For me it is the massive reliance on the campaign quest lines to open up features:
- 3 of my venthyr alts have yet to unlock their transport networks because of the required quest line. Same problem with 2 of my night fae alts
- 8 of my alts used the skip to Korthia, yet haven’t done the quests needed to open the archive, and their inventorys are filling with relics they can’t deposit
At least for legion and BfA, my alts leveled primarily from the invasion events. For SL, they leveled by holiday events over the past year, all of them reaching 60 at the end of last midsummer festival