http://www.jazzmusicarchives.com/miles-davis--circle-in-the-round.aspx" rel="nofollow - http://www.jazzmusicarchives.com/miles-davis--circle-in-the-round.aspx

Circle in the Round should be moved to compilations, as it features recordings ranging from 1955 all the way to 1970. 

http://www.jazzmusicarchives.com/miles-davis--water-babies.aspx" rel="nofollow - http://www.jazzmusicarchives.com/miles-davis--water-babies.aspx

The sixth track, Splash, is a CD bonus track not included on the original album. Water Babies' status as a proper studio album might be debatable, but instead of moving it to compilations I'd counter by moving 1958 Miles from compilations to studio albums, since it's all from a single session, except for the last track Little Melonae, which I think is from 1955 and duly dropped from the edition that came in my Complete Columbia Recordings box set and replaced with an alternate take of Fran-Dance. Wikipedia uses both studio album and compilation descriptions with 1958 Miles while placing it under studio albums in the discography. There's at least three different track listings for 1958 Miles; the original one primarily listed at Wikipedia (including stuff later released on Jazz at the Plaza), the newer pressing listed at JMA and the one I've got with Little Melonae cut and replaced with Fran-Dance.

http://www.jazzmusicarchives.com/miles-davis--1958-miles-aka-58-sessions-featuring-stella-by-starlight%28compilation%29.aspx" rel="nofollow - http://www.jazzmusicarchives.com/miles-davis--1958-miles-aka-58-sessions-featuring-stella-by-starlight(compilation).aspx

http://en.wikipedia.org/wiki/1958_Miles" rel="nofollow - http://en.wikipedia.org/wiki/1958_Miles

If I'm right all material presented on this album is released here for the first time - so we count it as regular album, not compilation. On JMA we understand compilation as collection of previously released material. In jazz there are lot of studio albums completed from different previously recorded material (which haven't been released before)

corrected

"1958 Miles" is true compilation album - released in 1974 (in Japan) it contains whole A-side(3 compositions) from studio album "Jazz Track" (originally released in 1959) plus two more compositions (from live album, released in 1973),what means it contains only previously released music. When possible, our added albums always are original (first released) versions. What is stated as Original Track List on Wikipedia for this album is obvious mistake - released in 1974 as single vinyl ,this album's Side B (or Side 2 on Wiki) contains more than 30 minutes of music, what is technically impossible.I expect our added track list is real 1974-version Japanese vinyl track list, never saw the original though.

Ah, ok, that makes sense. So how about Directions? It contains all unreleased material, but a few tunes were released before as different versions. Most of it was brand new but I suppose it stays as a compilation because of tracks 2-4? 

http://www.jazzmusicarchives.com/miles-davis--directions-unreleased-recordings-1960-1970%28compilation%29.aspx" rel="nofollow - http://www.jazzmusicarchives.com/miles-davis--directions-unreleased-recordings-1960-1970(compilation).aspx

It indeed seems there's no truth to Wikipedia's "original" 1958 Miles track listing. The only LP version Discogs.com is aware of was released in 1979 and included the tracks already on JMA. It could be mentioned on the album's page, though, that the pressing included in the Complete Columbia Album Collection box set omits Little Melonae in favor of Fran-Dance (alternate take) (5:52).

http://www.jazzmusicarchives.com/miles-davis--the-complete-columbia-album-collection%28compilation%29.aspx" rel="nofollow - http://www.jazzmusicarchives.com/miles-davis--the-complete-columbia-album-collection(compilation).aspx

It's difficult to find out in this case which versions of songs are used on this release, if we'll believe that album's title is correct we can expect it contains unreleased songs or versions. So here I agree with you - it can be moved to "studio albums" section

added

According to the booklet of the Complete Columbia box set, the version of 'Round Midnight was recorded at the Blackhawk on the Saturday night in 1961, apparently first released on Directions and only much later in the Complete Friday and Saturday Nights at the Blackhawk release. 

So Near, So Far was recorded on April 16, 1963 whereas the version on Seven Steps to Heaven was recorded on May 14. The April 16 version was later included as a bonus track on the current Seven Steps pressing.

Limbo was recorded on May 9, 1967, the final version on Sorcerer is from May 16. Again the May 9 version is nowadays found on the Sorcerer CD as a bonus track.

So yes, according to a very good source all the material saw its first release on Directions