Does anybody remember four years ago when the TAS DVD was released, there was a canon discussion then. I have a vague memory that when this happened, the studio had "re-canonized" it. Of course, I might just be recalling some fan discussion here or elsewhere. Anybody remember anything about that?
The Official Star Trek website was putting up encyclopedic entries on TAS and ran an online poll about wether it should be accepted as canon. And the poll was in favour of its restoration to canon, although no press release announced a change.
TAS was only actually made off-limits to the licensed ST tie-in creators from 1989 (hiatus before TNG Season 2) to September 1991 (Roddenberry's death). After that, the Star Trek Office at Paramount was closed and all rulings of what could and couldn't be used by the licensees passed to Paramount Licensing/Viacom Consumer Products, now known as CBS Consumer Products.
It seemed pretty dumb at the time to tell writers of TNG and the tie-ins that their scripts and manuscripts were beholden to events in under eleven hours (22 episodes) of a then-rarely seen animated series by a now-defunct company. No networks or syndicators were running TAS in 1989, it wasn't out on commercial VHS in many countries, was virtually unknown to the new, young audiences of ST IV and TNG, and the back catalogue of Filmation products were in a stat of copyright flux.
Richard Arnold wanted us to stop expecting to see TAS as a canonical element of the franchise, but he hasn't worked for the Star Trek Office since GR died.
Paula Block approved a brief reference to Phylosians in the novelization of "Unification" and we haven't looked back since.
In short, TAS was put on the shelf for legal reasons related to the shutting down of Filmation, and had nothing to do with the perceived quality or "worthiness" of TAS to be considered part of the Star Trek canon. That Roddenberry didn't feel it necessary to explain this legal nicety to his gofer Richard Arnold really isn't surprising, nor is it surprising (sad, but not surprising) that Richard was allowed to continue in his "GR doesn't like TAS anymore" fantasy because any comment from Paramount, pro or con, likely would've played holy hell with the negotiations over the rights to TAS.
Once those rights were secured, TAS was back in the fold. Rick Berman just forgot to make an official annoucement.