We're 5-6 with an epically horrible offensive line...what if?

[*ochocincos*]

I see the Bengals winning 1-2 more games this year, putting them at 6-10 or 7-9. Bears should be a win and Ravens maybe.
In terms of what would Whitworth and one more upgrade on OL have done, I'd say an extra 2-3 wins against those four games you mentioned.
But at the end of the day, the Bengals need to be able to beat the actual contenders if there's hope of winning a playoff game, not just beating all the other bad teams just to get into the playoffs. Traditionally, the contenders have owned the Bengals in recent years save 2015.