Observing a review aggregate of several individual games and making qualitative statements based on it is sketchy at best. There's a wide variety of cumulative circumstances affecting the impression each game left on the reviewers at the time of release. They don't exist in a vacuum, and contemporary perspectives can wildly differ from those held in the past.
For example, Circle of the Moon is rated so high not because of any intrinsic value found in the game itself (don't start), but because of several tangential factors that made it appealing at the time. It was the first of the games following in Symphony's footsteps, it was a Game Boy Advance launch title which gave it an elevated status of importance, it was a showpiece for the capabilities of new handheld technology, it was a return to a more accepted form of 2D play after the badly-received N64 titles... all of these affected its overtly glowing critical reception in its day. It is nowhere near as highly-regarded in retrospect, even if its contemporary reviews give that impression.
More issues come with rereleases like DXC: the port quality is crucial, as well as understanding its nature as a compilation. A singular review score of the Dracula X Chronicles cannot be taken as a definitive critical statement on Rondo of Blood, Symphony of the Night, and the 3D remake of the former all in one. It should be an evaluation of everything contained in the release, which is indeed three very different games, two of which are ports of the originals (not very good ones at that), and thus ill-suited for serving as an accurate reflection of either game's merit as found in their original releases. Multiple levels of competence have to be taken into account in reviewing releases like that, and I'm not confident every writer did.
Rereleases also do not carry the same critical impact as their original counterparts, even if the porting quality is equally good or close to it. The Double Pack is rated lower than either of the individual releases of the games it contains in flawless quality. In objective terms, it's superior to either Harmony of Dissonance or Aria of Sorrow simply by the virtue of featuring them both, but it is still just a rerelease of well-trodden material, however well-made. Its release happened only a few years after the original games came out, and on the same platform no less, so it didn't warrant a lot of excitement in the grand scheme of things.
If anything, services like Metacritic possess their most useful functionality in cataloguing a database of reviews written about a subject, and providing links to those articles. Researching critical assessment should be conducted by reading on a case-by-case basis, not by staring at how numbers compare to each other.