Steam Deck

That's reasonable, but the market's already flooded with generic controllers at various price points and degrees of quality. If the idea's to make money, the new design won't do brilliantly as things like the awkwardly-placed trackpads will increase manufacturing costs without being a killer feature that makes most people prefer to spend more on this particular controller. If the idea's to make something viable that hadn't been before (which is what Valve normally seem to go for), then this isn't serving the discontinued Steam Controller's niche as effectively as the original did, and isn't serving any new niche, either.

By the way, the thing they were trying at the same time as the original Steam Controller was the Steam Machine, not the Steam Box. It also kind of did work, as the couch PC gaming part mostly happened, but it took a decade of improvements to Proton and abandoning third-party hardware manufacturers before Linux-based console-like PCs became viable in the form of the Steam Deck. Ten years ago, nearly no games ran under Linux, and all the Steam Machine manufacturers were just changing the logo on one of their existing prebuilts and charging an extra $100 not to install Windows on it, so you were better off with any other desktop.