I would say that the mg7 Atrios improve upon the mg5 Atrios in mids some and treble significantly while bass remains about the same. I personally would not report much of an improvement in soundstage although the enhancements in treble help improve the overall dynamics. I can't comment on mg7 Atrios for classical as I haven't developed an ear for it, but I find them quite adequate for jazz due to the newly added treble sparkle and (imo) best-in-class sub-bass extension. Again, I agree that soundstage could be better, but in well mastered jazz recordings, I don't find instrument separation lacking. Most importantly, I find the Atrios to be quite musical, more so than any other IEM I own or have owned.
Unfortunately, I haven't heard any of the other IEM's you listed (I'd love to try out GR07's) so I'm afraid I can't offer comparison to them.