"Release the game early to make money so we can continue work on the final product" seems to be the motto for just about every MMO ever created. It has certain degrees but far as I can tell they are all guilty of this in some way. Far as I am concerned the tactic is fine so long as the launched product has enough too do and have "fun" with that I dont feel I am paying (insert company here) to beta test their game. Warcraft was lite in the content department when they released it and could of used more time in production but what they released was great... so no harm done. On the flip side EQ2 was pure shit and paying them to 'fix' their product left a sour taste in my mouth.
If Vanguard released with enough to do and enjoy for a few months I dont see the problem with them taking box sale profit and continuing to finish what they started. So long as they dont do the "omg look at all the free content we are giving you!!!!!!!!" when they do something like release Berserkers. Which is something that has always annoyed me about other companies. Not 'everything' needs a PR spin put on it people.. its ok to say "sorry it took us longer then expected to finish this... but its here now so enjoy!".
If the game is decent at release I wont lose any sleep at night knowing my money is going to make the game better. I mean if EQ2 can go from being complete shit at release to a good game I have faith that any game can redeem itself and end up being worth the monthly sub.
