I have three alts that I play regularly, two at max level.

What I'd like to see:
- shared housing between all alts on the same data centre (was promised, not delivered so far)
- alt characters able to mail each other
- Mog-station purchases made account-wide (might not be practical judging from some of the things Yoshi has said in the past)
- the option to have our achievements made account-wide

Compared to other games FFXIV is not very alt-friendly. I know we don't need alts but if I didn't have mine, I'd probably have been playing another game since early spring. My alts give me a reason to stay subbed and I'm happy to pay a little extra for them; however, I do think the game could accommodate players like me a little more.