I'm in the same boat as you - running a personal/friends/family mail toaster for 16 years now. But I disagree that Google have made the administration harder. Internet mail servers don't live in isolation, and context has always been changing. I have no issue with adapting configuration as expectations change, so Gmail's evolution has never inhibited my ability to exchange email with the world. This move is no different. Really, I feel that the elephant has been tremendously careful
not to tread on the mice.
I don't believe this particular change materially improves security, since it isn't representing an end-to-end behaviour, but if it raises awareness and challenges mass surveillance then so much the better.
Personally I would like them to advocate for other necessary infrastructure advances and include, for non-IPv6-capable MTAs, an icon of a lurching monster that refuses to die.