Meh, destroying the Federation and Earth isn't all that new of an ideal in Trek. In a way it's a tradition: if you want to show how screwed up your future/timeline is, you nuke a the Federation. So it comes off less "He is dissing the old timeline!!!!" and more "Oh for fuck, this again?"
Yes, it's taken me a while but I've finally come to that conclusion as well. The destruction of Romulus could just be in the future "All Good Things" timeline if necessary. Whether or not the Earth and the TNG crew had ended up destroyed there too, wouldn't have made any difference ultimately. To fix that and carry on writing adventures for them, you'd just retcon Nero and Spock as having come from 2387 in an alternate to the Prime and proceed by avoiding or changing the outcome to that whole Hobus event.