This definitely looks better and more realistic than before. I had this in mind at one point long ago but forgot to bring up the subject here. Since this is really only a question of upping the limit, it will give mission designers the option to use the higher limit while having older missions work as they did before, so there's no reason not to go for it.
The swirling thing is a neat effect but it does indeed get quite annoying when there are that many stars. Is it possible to do it only for a few of them (randomly selected) without dropping the framerate significantly?
I keep the nebulas the same for all missions in a system, but nobody is really going to notice the star thing unless there is some glaring change.