Re: Alternate timelines - What can you mess with???
Hmm. Some exaggeration here if you are referring to the reception to your piece in Critiques here on Chrons. No one "slammed" you -- we merely pointed out that events in NI were too recent for the whole thing to sit comfortably here in the UK, not least as it would be seen to be referencing the Troubles even if that was not your intention. It would necessarily raise a lot of hackles and therefore lead to more difficulties in your selling the work. It's up to you how much value you put on that.
You can re-invent what history you like, but you can't expect people to be happy if they or their families have been caught up in events which you appear to be trivialising. So as far as you're concerned "a few hundred people killed in... a small scale revolutionary conflict" might be nothing worth getting het up about. To those whose husbands/fathers/mothers/children were killed -- and who are still mourning their losses -- this will come over as appalling insensitivity, if not worse.
There is no taboo. If you want to write an alternative history in which a child by the name of McCann is kidnapped from a resort while her parents are dining, or the story of a prophet who comes out of the desert to form a religion which several hundred years later leads to adherents flying planes into skyscrapers, do so. Just don't expect them to be well received by those who are still affected or who have identities bound up with those histories.