The short... yes, he has been wasted. The todoroki family drama got old pretty quickly and what the author did with it was simply not interesting. At this point I don't care if touya survives and redeems himself or shoto rips out his heart with his bare hands. Any end to this is better than what's been going on.
That said, this isn't really a shoto thing, there's plenty of characters with whom the author simply failed to do anything fun with. The manga's peak, which seems pretty high up from where we are at now was easily the kamino battle (the battle between afo and allmight). Since then the manga has been pretty much free falling. A definitive lowpoint is the hisaki arc which was infuriatingly stupid. Heroes were shown as comically incompetent, hisaki wanted to modernize yakusa by turning them into cackling morons like the other villains... We were introduced to midnight, the absolute worst waste of ink this manga has thrown at. He was such a garbage character that he died a miserable death after a life of regret and it was still too good for him. Then villain's development... a lot of villains claimed to have ideological affinity to stain but not one of them ever lived up to that. Villains did start with a semblance of ideology but all of them simply evolved into cackling maniacs who revel in the blood and pain of the innocent. None of them are intelligent, none of them are interesting, none of them are redeemable, none of them are worth the time. They are merely rabid animals who should be shot down on sight. There was a time when I made the point at least some of them were too mentally ill to even be evil and the correct/humane way of handling them would be to keep them at mental asylums while heavily sedated so that they are no longer threats to themselves and others. But we are at a point where even that is absurd. At this point they are merely unhinged military threats. The correct way fo handling them is without prejudice until they are dead. Not one of them deserves more or better.
Oh, and to add insult to injury, shigaraki. In fairness he is redeemable because the "shigaraki" persona is basically a fake person created by AFO literally pumping tomura full of actual hatred over many years. So the story's big bad is not even a real person in any way that matters.
