I really like mine, despite very limited use so far, so I can't really comment on the heat issue.
The barrel can be removed, although it's apparently easier to get congress to stop sending money to Ukraine...
It's rumored different barrel profiles will be available, one day, sometime....
If you shoot out a JAKL barrel, I'm pretty sure PSA would re-barrel it for you. Assuming you could afford postage after buying all that 5.56....
The JAKL fairy is alleged to be coming out with a JAKL that takes AK mags and chambers 7.62x39 AND 5.45 interchangeably, once you figure out how to get the barrel off...
They also claim to be coming out with a 7.62 NATO JAKL that takes Pmags, but not Glock mags. I imagine when the 7.62 Glock carbine comes out that will change...
Joking aside, I like it a lot. And I really am looking forward to the Russian Collusion version, with the initial run featuring a cameo of Trump and Putin engraved on the lower....