Agreed, someone on another thread else posted a very interesting idea that there may be things about canon that are essential, and some that are non-essential. I agreed with that, and that may be the root of some of the changes. Of course for some all canon is essential and that's fine too, but I feel there can be a line drawn at a certain point about what's totally necessary and what isn't. Of course, J.J's line may not agree with everyone - if that's what he's done.
And I used to consider myself a canonite for a long time years back, until I realised that I actually wasn't - as long as the essential pieces are there I can work around the rest. I don't apologise for that if it doesn't go down well with others.