(...) And we can always still play 8th...
Most likely that.
Unfortunately for fluff enthusiasts (me included), over the years GW has proven one too many times it doesn't seem to give a crap about it. But even worst than that, they also dont care about the dramatic changes on the game that they induce, every time a new army book or rules edition gets out.
My oldest army in my shelves is Chaos (started play them when Chaos was "
undivided", as in "
every thing in one single army book", not this Warriors/Beastmen/Daemon everyone apart thing), and I've lost cont of the times all of the sudden, with a new book out, half my army units became useless.
So getting back on track and as quoted above, if rumours to the new Ed. get to be accurate, to remain in the 8th Ed. might end up being a sensible option for some of the most scrambled army's.