Besides the fact that most of these pieces in question (excluding Larsson) aren't 'virtuosic display vehicles' (they're still pretty hard, though), I think that Sauer's playing here is 'true to the music'. If anything, they are very good 'middle of the road' interpretations that I would recommend to a student who may be learning one of these pieces. Lindberg can sometimes go a bit overboard on some pieces like those represnted here, and give an unorthodox interpretation that could send a student down the wrong road. Sauer's career as primarily an orchestral trombonist has probably put him into the habit of 'playing the ink', while guys like Lindberg can get away with being a bit 'creative' at times. In terms of being virtuosic, I think to be able to play a solid valve-register D on a straight tenor and then go all the way to articulate a High F-Sharp (I mean high,high F#) is still impressive. His execution of trills, mordents, and other ornaments is also well done.
There aren't that many Trombone Recordings around the place, so I don't think we can be too picky. Nevertheless, this is still an excellent recording. Buy it and decide for yourself.