I'm hoping Odo will be around long enough to pick up the changeling and Kira threads previously dangled. After that, it will probably be occasional guest spots.
As Kira is obviously not dead - The prophets don't seem to be, Sisko had that vision, and Kira is in the wormhole - and is mentioned in the blurb, I think it's quite likely we will have her back and before the wormhole reopens (and we get Kira back) Odo can't get back, so I think it is very likely that Odo will stay some time. And in The Worlds of Deep Space Nine 3
Odo was thinking about going back to Kira anyway.