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Hehe indeed ; and if it comes from a genuine place, then it sounds like "whatifs" from someone who hasn't worked on many models.

To the OP :

"A UV co-pilot overlays stretch/TD heatmaps, proposes seams you can accept/tweak,"
"wouldn't something like this be cool?"

Well not really, since seams are placed (or at least planned ahead) *while* modeling the low, as they very much influence the modeling. Hoping for an assistant to design them for you after the fact is somewhat absurd and wouldn't be much better than the many automatic or semi-automatic UV tools already available today.

What you are describing is close to one-day throwaway models that are not meant to go in the final game. And while such quick models can be interesting experiments (and as said they can certainly be done in less than a day with the currently available tools, ie tools that have been available for about 10+ years already), in actual practice they're not so hot as ingame placeholders since they take about the same time to do as a regular clean blockout ... and a clean blockout has the big advantage of being a starting point for the final model later as opposed to being fully throwaway. As a matter of fact it seems to be what Valve is doing with their Deadlock models. And if production needs to speed up unexpectedly, a clean blockout ready for quick cleanup and texturing will always be more useful than a sculpted model bruteforced into a pseudo-realtime model that needs to be redone from scratch.

Now of course new tools are always fun to think about (and certainly interesting to develop). But I genuinely believe that the time of an artist is better spent on developing efficient working habits with the tools available today, than on daydreaming about the next automagical thing.