That was the premise of the post. Had we drafted Lions' current LT Riley Reif with the 9th pick instead of Keuchly, we would at this moment have a starting LT and Beason to man the MLB position. Meaning a better running game and passing attack, and the defense would not be that far off with Beason as the MLB. Had we hired an offensive minded coach instead of Rivera this likely would have been the scenario. Offensive coaches tend to draft OT after they find their franchise QB(if they don't already have one). Cam was drafted in 2011 and Riley Reif was drafted in 2012 with the 23rd pick by Detroit. That could have been the pick instead of Keuchly. At this moment we would be set at LT. Our only concern this off season would be WRs and secondary.
It's a dumb premise, primarily because Beason is nowhere near as close to Kuechly as you think. Heck, he was benched for being a liability even before he was traded.
After this offseason's free agency and draft, we could be set at left tackle and have a superior middle linebacker, as well as addressing other position concerns.
Drafting Luke was the right choice, and no amount of spin you can try to put on it will change that fact.