I reckon they'll be midtable next season, shouldn't be troubled by relegation but won't be troubling the playoffs.
Gas logic says they are coming for us because they've made some good signing on paper but they need to get by Wigan, Charlton, Hull (if they somehow get their act together), Sunderland, Ipswich, Peterborough, Doncaster, Portsmouth, Plymouth and Oxford.
I've said it before but the gap between league one and the championship is growing and I expect it'll be the same few teams that fight it out for promotion/play offs. One good season may get you up but you need a fair bit of luck and investment to stay up.