1) Update 19 - Nothing but bug fixes and quality of life improvements. The list of bug fixes should be at least 4 pages long. Included in these fixes is that every single item, spell, and ability has its bonus type specifically quantified to eliminate any possible confusion about what stacks with what.
2) The expansion - Without changing the price, the expansion is...expanded. Instead of 2 adventure packs and 2 explorer areas, the expansion is bulked up to include: 6 adventure packs (5-6 quests each), 3 explorer areas, 4 raids.
3) The Enhancement revamp is cancelled, because it's an irretrievable mess that never should have made alpha status. Instead, all classes have all of their PrEs implemented and taken to Tier3 (or Tier5, if it's set up like Archmage).
4) Dump the entire epic TR program, and particularly eliminate even the slightest trace that the devs even considered for a microsecond stripping out people's hard-earned ED XP when TRing.
5) Go ahead with the XP smoothing on TR2+. Spread out the burden currently lumped at 17-20, and spread it down to 12, so a much larger number of quests are available to get that XP.
6) Split heroic and epic quest completions so that repeat counters are not affected for L20+ dungeons.
7) Stop showing utter contempt for your customers. Yes, customers. Not players, CUSTOMERS. You know, those people who quite literally pay your salaries?
The last one will be the hardest.
Some of these would make me come back....but I gave up on waiting a month ago and just bailed.