Why would I? No, seriously, Gen1 that I have in use works.
You tell me that list of breaking changes i sa lie?
I'm not telling you anything.. I'm asking if you have tried it.
You have a very functional Hyper-V environment? It shouldn't be difficult to start a new Gen2 system to see if it works.
I haven't touched it for a bit, from memory though, ths biggest difference was thaf Gen1 was traditional BIOS and Gen2 was UEFI, which CHR has added support for. Just be sure to turn off 'Secure Boot'.
Also, are they stopping Gen1 from working? Or just not letting you create new Gen1 systems? It is M$, could be either.