There no logic in hoping that new people keep coming. With a high turnover rate will only allow for a lot of bad reviews which will turn away new people from even coming into the game.
But since it's free, people may be more willing to try playing regardless of the reviews. On the whole, reviews mean less to a consumer if you don't have to pay to try it for yourself. The biggest reason people read/listen to reviews is "is this game or product worth the money". A F2P title costs no money, so the reviews hold little merit. Now if a string of professional reviews start claiming that STO F2P is so bad it's not even worth your time (which truthfully is not out of the realm of possibility), you may have a point.
Also, people can stop playing and still give a positive review. If you play for a couple months, exhaust what content there was but enjoyed it, you could easily stop playing, yet not leave the game with a negative opinion (aside from perhaps that there was too little content).
But by looking at the changes Cryptic has made for the F2P model, it's abundantly clear that they're targeting the high turnover, casual MMO gamer market, perhaps hoping to con a few dollars out of trek fans who would pay to have a more "trek-like" experience with canon ships and uniforms.
The argument that leveling is too fast, so people will hit level cap and say "there's nothing to do now", doesn't make sense - because at the current leveling pace, when you hit level cap there's still several fronts worth of story missions to play. (Unless you're KDF. Sorry, guys.)
Why do you want leveling to go slower? Do you WANT to run out of content before you run out of levels, and have to grind to reach cap? I don't understand. I thought most players agreed they were against grinding.
America may be full of idiots, but there are only 312,842,000 suckers at best (and given the learning curve indicated by the reaction to the bug hunt, I wouldn't count on that many). From there on down the numbers get even less suited to banking on the turnover business.
it took me something like a year of extremely casual play to level to Captain for the first tiem. I've made it to level 39 in the matter of just a couple of weeks of doing almost nothing aside from poking the doffs and running Q's ice races.