Is An FX-8370 Viable For Emulation?

It depends on the game, overall you won't get the same performance you'd get with a decent CPU but it's a nice performance boost overall. Just overclock to a sweet spot and stay there. Mine is 4.6GHz.

TSX Instruction Set is a plus, Intel architecture over AMD due to the CCX latency issue, and lots of cores like i7 8700K or i9 9900K (but not too many like Threadripper).

You didn't mention clock speed- I'm guessing it's not as relevant here?