You're both right, sorta. Kubo said that he wants to do something with Hell, and he wants to do more with Kenpachi in the same interview, because Kenpachi's his favorite.
I can see it going one of two ways.
1. Fighting in Fake Karakura happens. Aizen either sends everybody to Hell, OR Ichigo and co. get out of Hueco Mundo by going through Hell. Either way, Aizen gets his key. Showdown on the King's Throne happens. Manga ends. This will probably take something like a couple years, given Kubo's writing style.
2. Fight in Fake Karakura happens, Aizen gets the key, showdown on the King's Throne. Aizen probably dies (OR DOES HE?). Everything looks to be good...new enemies from Hell show up and start wrecking everyone's shit.
Of course, if he goes with 2, sky's the limit to how long it'll last.