I think getting the left handed Tua goes hand-in-hand with the thinking. Tunsil is soon to be overvalued for us in just the ways you list....elite RTs can be had for typically less than elite LTs in the draft/FA. On top of that I think we got above market value for the trades as-is, on a league-wide basis. So factoring in our specific situation just made the deal impossible to pass up. But it does make getting Tua absolutely imperative.After giving it more thought, I have another angle to view this trade that makes me more comfortable. We'd have to re-sign Tunsil to be the highest paid LT in the league in a few years. Of those, this year we don't need him, because we're tanking and do not have our QB yet. Next year we will need him to protect our QB, but we'll still be tanking. Essentially, the rest of his "contract" would be during a time we don't need him. As soon as we need him, we'd have to pay him the highest salary of any OL in the league. Instead of that, we got 3 high draft picks. Looking at it that way … it's more palatable.
Sure, we'll need a LT to protect our rookie QB in 2020 (or RT if he's a left hander like Tua). But, we can use one of those 1sts to get a LT prospect. Even if he doesn't work out, we have someone with whom to build the OL, and by then hopefully Julie'n Davenport will have developed into a serviceable blindside protector. Maybe …. maybe not, but it's worth those draft picks to take the risk.
Seeing as we're giving Jesse Davis some cross-training at LT, he might be able to play there if we draft Tua, because it will not be his blindside. I'm feeling better and better about this trade, despite it being potentially problematic for our young QB in 2020.
To me, the litmus test will be what we do with those picks, and whether we can find a decent blindside protector for our QB allowing him to develop. Wasting Tunsil's best (and cheapest) years isn't worth losing out on those draft picks.