Uh, folks. It's not open to opinion, anymore. TAS is
now canon. It is confirmed that is canon at StarTrek.com
Here is a quote taken from Star Trek's official site...
So the question remains, is Star Trek: The Animated Series (or Animated Adventures) canon, or not? We would like to think so, if only so we can make more work for ourselves and all future historians! At some point, we would like to start adding more information to our site gleaned from this show and have it form part of the overall collective consciousness of Star Trek. Or, do we simply leave the whole issue ambiguous and let the fans decide in their own mind what they consider canon? Put to a recent vote on the site, fans favored the canonization of the animated series by a margin of more than 2-1.
http://www.startrek.com/startrek/view/news/editorials/article/17178.html
See, the studio actually said that they prefer to think TAS is canon. Which essentially means it
is canon because they would like to think that it is.
And StarTrek.com (as you know) is owned by CBS Studios...
http://whois.domaintools.com/startrek.com
Trust me, I would prefer not having the Animated Series considered as canon. It is after all a 1970's cartoon we are talking about. But the studio says it likes to think TAS is canon. Then it is canon. No if's ands or buts. It is spelled out and confirmed right on their very site.