As someone who hasn't seen a Marvel movie since the first Avengers movie (and the five or so movies leading up to that), and as someone who doesn't really read comics (Marvel or otherwise) much at all, yet nevertheless still probably knows more than the average person about them simply via the Internet and via mere cultural osmosis, I have to admit that I don't really have the first clue about who the fuck Kang the Conquerer is, nor do I really have any interest in finding out more, aside from what very little I've already bothered to read about him online or whatever. To me, Kang is either a Klingon, one of those two aliens on The Simpsons, or a character in Mortal Kombat. As such, yeah, I pretty much agree with Pat and Woolie that the whole MCU Kang thing was pretty much a non-starter, at least as far as I gave a shit about it.
Robert Downey Jr. coming back as Doctor Doom could be cool, though, regardless of whether they tie it in with RDJ previously having been Iron Man or whatever, and it is (relatively speaking) far more interesting to me than anything (MCU) Kang-related. Maybe I'll even watch his movie(s) at some point after the decade or two it would take me to get caught up on the rest of the MCU movies (at the usual rate I watch movies at all, these days, which is seldom, unless I go nuts).