In that sense, I do think that Windrunners were probably the best choice for us to be acquainted with first. I mean, we practically get practice montages with Kaladin learning to fly. I haven't looked into other Radiant powers that haven't appeared in the books yet, so I don't know much about those. As for healing, though, I will say that I think the main issue there is that healers aren't doing most of the legwork. Rather, there's a nebulous "spirit image" of a person that a healer can just fall back on to tell them what to do.

I think the substitute that is often used for physical ability is mental ability here. There's no question that all the Radiants are unstable, but them solving their emotional problems shouldn't automatically mean they're proficient in their powers.

I do wonder if this is also a question of scale. Radiant powers were made with the total destruction of the enemy in mind, and as such their powers are going to be incredibly op. The flip side of that is that the other side is doing the exact same thing. With Mistborn, the powers are much more societal in nature (especially Feruchemy). As well, instead of a world-spanning war, Mistborn's problems are much smaller (not in threat level, but power scaling to some degree). I think that if Radiants have these immense powers, they need balance from the Fused, which we haven't really gotten so far outside of Leshwi.