A lot of stuff is sacred in 3E. BoED is choke full of sacred stuff
Also nothing was truly sacred in 2E. They blew up half their settings back then for fun.
Now, if the new aboleth looked like one of those, that would be pretty cool. I picture an aboleth as looking something like a piece of raw chicken trim that's been floating in dishwater overnight, plus tentacles, fins, and weird crustacean-like features.