My two cents. I agree that the RVG remastered CDs, while many are creative master pieces, sound noticeably thin. And I think the ones from the early sixties sound more so than the ones from the late fifties as a rule.
Theory one: RVG's original recordings were engineered for home systems commonly in use from the mid fifties to the mid sixties. If my dad or others of this generation that I knew are any indication, they were using large console systems or stand alone tube amps with just OK cartridges and turntables and big boomy drivers. RVG's recordings were engineered "hot" with bumped up the treble so that you could hear the cymbals and horns in some proximity to live versions on HiFi gear in use at the time.
Theory two: RVG is re-mastering his original recordings for use by current audiophiles who he assumes are using tube systems and he has purposely engineered the sound to compliment the bloom of the tube based systems (OK, this seems unlikely).
Theory three: RVG now thinks the bright remastered CD versions sound just fine to him on a boom box or a $200K stereo.
Anecdotal evidence: I have an old Verve LP of Ed Thigpen engineered by RVG in 1962 at his studio and it just sounds marvelous on my not so fancy SS system. No tubes to sweeten it up. Compare that to original recordings RVG has re-mastered of works by Wayne Shorter, Lee Morgan and McCoy Tyner around the same time that sound a bit hard and thin to me (but extremely clear) in comparison to this old analog recording, and compared to modern Blue Note and other jazz CDs I own by various artists. I also notice much less of this effect with reissues of Columbia jazz recordings from the fifties (e.g. Dave Brubeck, Miles Davis, Charlie Mingus, etc.)
I am not so sure theories one and two hold up under much scrutiny. The material in most of these old recordings is top of the heap, and if you have tone controls, worth getting and monkeying with the sound until like what you hear. Or find good copies of the original vinyl and be prepared to pay $20-$50 and up a pop.