I'm chimin' in a little late here, but I agree that this would make a fine box, as previous reissues have been spotty. I do have a few comments about several of the records, all of which I've owned for years.
"Who is Gary Burton?" There's some fine playing on this one, although it seems a little unrehearsed, and the LP is a little unclear as to who's playing on what.
"The Time Machine" Burton's "experimental" album, with overdubs. Nice in places, but it doesn't all work for me. Criticisms that Burton can be "mechanical" or perhaps not spontaneous enough can easily be levelled at this one.
"Something's Coming" A superb and overlooked set, perhaps due to its rariity. Jim Hall is on board.
"Tennessee Firebird" A noble attempt to fuse country and jazz, but it doesn't come off completely.
"Duster" A classic and seminal album. I saw this group live at the time, and they were smokin'.
"Lofty Fake Anagram" & "In Concert" Less compelling than "Duster", perhaps because the drum chair is occupied by Bobby Moses, not Roy Haynes (a personal preference, of course). Still pretty good, though.
"A Genuine Tong Funeral" This is really a Carla Bley album on which Burton is featured, but no doubt Burton's deal with RCA is what got it made.
"Country Roads" This is Burton's masterpiece, far and away my favorite Burton record, and his last for RCA.