Given that X3 is up in May and there are big creative & team changes mid-summer, it seems highly likely that Phoenix will be back in the near future - properly.
Brubaker is taking over Uncanny, we know Nightcrawler & Rachel will be there but he's also hinted with regards to his future roster:
Carey taking over X-men (Cable, Mystique, Sabertooth, Rogue, Iceman, Cannonball) has referred to Bachalo rendering a mysterious not-yet-named character in such a way that it was impossible not to use her.And one of the most important characters from X-Men ever, too, but I can't say who yet.
Then you've got Whedon on Astonishing who has the cast most likely to be affected the most by her return and has stated that his next arc(s?) will be quite centralised and internal. Phoenix would certainly give them a reason to be, plus he's already shown his affinity with the galactic, given SWORD & Breakworld which may well be feeding into Phoenix's return.
This isn't about what you'd like to see happen (personally would prefer her to stay dead, but that's irrelevant), but what you think will happen or would work best given the current & upcoming state of the X-verse.
Why should she come back? What creator? What story would make it worthwhile? Should it be a fully powered Phoenix Jean that comes back, a regular powered Jean Grey or somewhere in between? It's obvious she needs to go somewhere new, but how could her character develop?
(I did search and couldn't find a thread on this exact subject that seemed relevant, shoot me if there is and point me in the right direction please)