My main worry is the glorification of illegal intelligence activities, contradicting the message of Deep Space Nine. If the movie can handle that barrier, fun and silly sounds great.
Yeah...I think a lot of that will depend on what the actual plot of the thing is, and they've been keeping a surprisingly tight lid on that.
The covert mission to destroy Cardassian weapons that Starfleet Intelligence sent Picard, Crusher, and Worf on in "Chain of Command" was probably illegal, but I never hear people complaining about it.