First for me would be housing. I've always loved player housing in the games I've played previously that have had it, and there are definitely ways to implement it that would make it interesting and useful and community-based. I know people keeps saying that that is what guild halls are for, but, you know, I'm part of two decent sized guilds and I have no input into our guild hall. I visit my home instance daily to use nodes, but I'd be there plenty more if there were things I could actually do to customise it to my taste. Second would be more world bosses and zone meta. My play schedule and time is often a bit all over the place, so I often feel uncomfortable with trying to get too involved in anything where other people are relying on me to be there and play for x amount of time, so I avoid a lot of group instanced content because of that, and have only infrequently participated in dungeons and fractals, and wouldn't dream of touching raids. Massive world bosses on a schedule, however, I can drop into and participate and it's not really going to affect anyone else if I suddenly have to drop out, so they work great for me. Third would be a great story - I'm replaying the whole story currently with my newly beloved norn firebrand, and having a blast, so more of that please. And I love all of Dragon's Watch, which I guess makes me unusual, so more of them too please. And then another interesting new system like gliding or mounts will always make me happy. And fun collections and achievements, because I love those. I mean, I'm easy to please. I'll buy it anyhow so long as I'm still actively involved in the game when it's released, but the above are all the things I really enjoy.