Another of the new First Contact designs, we never get a really good close look at the Sabre in the film - the image on attached to this entry is from the "Star Trek The next Generation Sketch Book". According to the diagram in the new Encyclopedia (page 470), the Sabre class are very small - about the size of the saucer section of the original Constitution class. I've pegged them as being light scout ships; designed to support ships such as the Steamrunner and Akira in battle, or to operate on their own in reasonably non-threatening environments. Since we don't see an awful lot of smaller ships on Trek, I've suggested that Starfleet suffered problems with the Sabre when they tried to cram too much into her.

The Sabres suffered pretty heavily in First Contact - as did most of the other designs present, of course! Given their apparent age - based on the relatively low NCC numbers - and size I don't think they are really designed for mass battle tactics and that could be an excuse as to why we've seen relatively little of them since First Contact. In truth, I think the design is boring compared to the Akira and Steamrunner, and the creators seem to be using these ships more because of the generally positive fan reaction to them.