I don’t like Kerrnings shuttle or the U-Wing. But, both get destroyed in the film (way to spoil things, trailer) so the fact that we don’t see 'em again at least makes sense.
I don’t like the TIE Striker either. And I’ve a bigger issue with it than the other two ships. It seems like it serves the same job as the bomber, but looks like the bombers new replacement. So why not use the bomber? Is it just to have new ships in the movie? Hopefully the film will show us why we’ve not seen these things before and I also hope we find that it’s built for situations we don’t encounter in the OT. It’s got the long pod like the bomber, and that has me intrigued.