On the software side, basic tools like numatop don't work on epyc. That's because the the equivalent of the Intel uncore counters that measure infinity fabric (AMD's new Hyper Transport, like Intel's QPI) are not available. Perhaps the big three have the time to do these tools themselves, and the NDAs in place to get access to the counters. Since even their single socket offering has up to 4 numa domains, getting access to these counters is pretty important.
There is also a limited selection of motherboard offerings from just a few vendors. This won't impact some of the cloud providers (who do their own board design), but for the rest of us, it is a pain. We've had an epyc we've been testing. I'm its biggest fan, but the motherboard is terrible in an enterprise setting. Just this week I updated the BIOS on it to get the new AGESA. Unlike our Intel / Supermicro boards, the BIOS update wiped all the settings. Earlier BIOS updates have required a physical (at the wall) power cycle, rather than a remote ipmi chassis power cycle.