This work was done three years ago!
This just feels like more backward work to me
I actually do not think so. No one is proposing porting all the features or large features like Federation. That will be a lot of work. On the contrary, not porting small improvements to stable releases has resulted people putting together their own Frankenstein releases or move to non Apache releases into other distributions that backport changes.
But am not intending to block it in any way...
I have seen these type of discussions in a couple of the jiras In the end what goes in is a call of Release Manager. As long we are not backporting changes that result in huge stability issues or if it is mitigated with adequate testing, I do not see why back porting should be discouraged.