With unsuccessful campaigns at P5 USC and Tennessee Kiffin would be better off staying at Bama at least for another year. However it would be interesting to see what happens with Kelly at ND next year if he doesn't produce.
The reality is...Kiffin does not want to work for Saban anymore and would either be at LSU next year or will be a head coach. I think a job like Florida Atlantic would be smart for Kiffin to prove he can win and run a program then move up. 8 out of the 12 head coach openings have went to coaches with head coaching experience (including Shawn Elliott who was interim head coach for almost an entire season at South Carolina). AD's and schools want coaches that have head coaching experience and the trend is to hire coaches from the power 5 group...it is a smart move for Kiffin, IMO.