Sorry to be slow in responding, SM. I've really availed myself of a lot of help from my fellows in constructing and maintaining my gallery, and so I can see why you're anxious to start getting feedback.
I didn't look through all of the galleries, but I did look at those for series that I know as well as those showcasing material that's unfamiliar to me. I thought these were strong elements:
Episode IDs with screen caps. Brief IDs of the characters and the basic situation that the cel/sketch shows. Cels are pictures in motion, after all, and so it's essential with this kind of art that you share with visitors some sense of the action that the art you have freezes.
Interest in the artists represented. I can confirm that your
Inuyasha layout is indeed by the late Shouko Ikeda. That's her personal stamp in blue down in the lower right corner (the letters read "Shouko" in hiragana clockwise from the top right). The blurry stamp in red is that of the episode director, Tatsuya Ishihara.
I was also intrigued by the sketches on yellow paper (that paper is an indication that a senior animator is advising or correcting the work of the key animator assigned to this scene) for
Megazone 23. The collaboration of Narumi Kakinouchi and Toshihiro Hirano on this OAV is an interesting one: Hirano was involved in
Magic Knight Rayearth and directed the spin-off
Rayearth OAV. Kakinouchi was mangaka for the
Vampire Princess Miyu manga and was involved in the animation of both the VPM OAV and TV series, which Hirano also directed.
But as both served as chief animation directors, I don't think that either of them sketched any of the gengas, which would be done by key animators under their supervision. Or under one of the other two animators (Haruhiko Mikimoto and Ichiro Itano) who also received credit as chief animation directors. I'd say you probably need to do some extra research to see if you can identify a signature style in any of these that you can use to establish a specific artist. That said, the interest in doing so puts your gallery in a special echelon, as the identity (or even the influence) of a specific artist is becoming more and more important in this field.
OK, some areas for improvement. (Not

criticism, just suggestions

) You might use the gallery description field to give chance visitors a brief introduction to a series that you collect. Some are (or should be) familiar to most collectors -- CCS, Inuyasha, Slayers, etc. -- but some are unusual enough to merit giving their date of production, main director/animator personnel, and a thumbnail summary of the plot/situation.
Also, you should consider limiting the visible items to the main images, rather than giving spaces to mouth layers, partials, images of characters only partially in frame. These belong, if at all, in thumbnails. Or you can try doing a simple reanimation from your scans. There are good animation programs available in freeware. I've used Jasc Animation Shop 3 for years, as it's intuitive and menu-driven. But I see there are lots of additional options available for no cost.
Hope this helps. Thanks for sharing and happy hunting! (Just not on the same auctions I'm browsing...)