That's a bummer. I would have thought it was possible given it's the same socket. What's Intel trying to do, drive their customers to AMD?Intel, by design, made Z87 motherboards, even high end motherboards like mine from ASUS (Maximus VI Hero) unable to support Broadwell CPUs.
That's like Intel 101 for you, screwing customers any chance they get.
4790K is meaningless as an upgrade as my 4770K overclocks well enough and I have a Noctua cooler.