Miami drafted three first rounders on the line in recent years, when you look at Pouncey, James, and Tunsil. They used free agency to sign another as a high priority contract in Brandon Albert. Bushrod is a former premium LT.
The point? When you can never get the OL right, a byproduct is other units don't get talent infusion. You keep putting high investments into the OL (or is it the "LOL"), and other units suffer. Where is the high impact, stud linebacker? You can't get him by not putting resources on it.
As for the OL, you could make the case that Tunsil is the only one worthy of the pick where Miami made it. But Miami is so deficient on the line, they went wild on Pouncey and James. I believe Pouncey was the highest taken center...ever. Virtually every team in the league has solid players on the line that were drafted mid to late rounders. Getting a guard or right tackle later is pretty universal. Instead, Miami put first rounders there. Imagine Miami had a fourth rounder getting it done at right tackle and a third rounder at center. Then you would have freed up two draft picks in the first round that could been used at LB, S, DE, whatever.
To add insult to injury, the Dolphins' line isn't good enough. A ton of guards around the league are former college tackles. Miami has tried that with Thomas, Turner, Jerry, et al. But you've got to project better from college tackle to pro guard. Or just get a dominant college guard (like Dan Feeney in the next draft). The scouts just have not understood or gotten it right on figuring out guard.
Look at the Pats' interior line. They totally get what they need at interior line play in a way that Miami hasn't been able to do.