Personally, I feel that for the non Star Trek fan, any TOS movies will be extremely dated. I think First Contact is the one and only movie you could play as an introduction to trek because of all the films, it`s the one for me that the casual movie goer can enjoy. But really, if someone wants to check out pre Abrams Trek, they need to get in to the series in my opinion. If they like that, and get attached to the characters, then they can get in to the films.
Actually, The Wrath of Khan is perfect as an introduction to the films and Star Trek in general. What exactly is dated about it?
It`s not dated for me. But for today`s movie going audience, which can be very fickle, I can see the effects being a major deterrent.
Star Wars for example, is one of my favourite movie franchises, and many young movie goers who grew up with jar jar binks and so on dislike the original trilogy because of the effects.
Unfortunately, for lots of casual movie goers, old means bad. The sort of people that can appreciate a Logans Run, or even movies like Monty Python and the Holy Grail, History of the World Part 1, etc. are the 1%ers.
While I like a lot of classic films, I can understand that the majority of the movie going audience will not because they can`t look past certain things like modern day production values. And if Abrams trek was their introduction in to the Roddenberry universe, it`s going to be an uphill battle to introduce them to the TOS movies right off the bat.