The KR concept suffers from the same problem that James Bond's gadgets do - in the 21st century there is no longer enough room between "common" and "obviously not possible." The gadgets are supposed to be somewhere in between. That's hard to do in a post-Mythbusters world.
The 1982 car is old enough to be classic-ish now (at least when the example is in good shape). But the KITT concept was cutting edge, not retro classic.
It could work to put The Hoff back in the 1982 car for the show. But that's not a whole show. He & KITT could be a supporting characters along with some other younger people I suppose.
As for the KITT voice, I dunno. Even if it could be recreated I doubt it would be financially worthwhile. Probably best to either stick with the original guy while he's alive or else cast someone else.
They could always write it into the fiction that KITT's voice has been changed a bit from the old days. Like maybe mention some big loss-of-data in the past and say they didn't have the software to do KITT's voice quite exactly the same anymore. Etc.
"Sorry about that, Michael. KITT's core memory bank survived. But the user-interface software didn't all make it over. He's the same personality under there but you'll have to get used to a little change in the voice sound. We tried to get close."