The technical website improvement that would most benefit my reading would be a character tag system.
Example in a webcomic:
https://www.yafgc.net/In this system, the author tags each page with the characters who appear on that page. Clicking on the tag displays other pages with that character tag.
This system helps me keep track of which characters are which and remind myself of their back story relevance. It makes it easy to answer questions like "who is this again?" or "what was this character up to last?" or even "what is the history of the plot arc associated with this key character?"
In many ways, a character tag system is significantly better than a character bios page, since it's always up to date instead of dated back to the last time the author had time to update the bios. It also avoids issues with spoilers: if you are reading issue 10 and need to remind yourself of this character's twist in issue 5, you can do so without that twist being spoiler for anyone still on issue 3. The tag system also works great when there's some unintended ambiguity in recognizing characters (like a changed artist), and you can always skip tagging a character when ambiguity is intended.
For MCC, the huge number of different series, the long time between updates for some series, the propensity for most of the characters to be attractive women (so not as distinct from each other), and the occasional artist change all contribute to me having a relatively hard time identifying characters compared to most comics. I'd also guess that Daphne has proper scripts for everything, meaning which character appears on which page is already written down. Tagging older pages might be a hassle, but a partial rollout of the system wouldn't be a problem (e.g. only go back and add tags for long running series, and only when those series have a new update).
The business case for this is that occasional subscribers can be prompted to resubscribe by new releases to series they enjoyed. However, a new update to a long series isn't exciting if it's going to be a pain reminding yourself who all these people are. This also helps make the ultra-long series that are popular with longtime subscribers also appealing to new and occasional subscribers. Finally, it adds a feature that incentivizes a subscription relative to reading PDFs.
I'm sure it's a bigger technical challenge to add tags to the MCC site than to a comic site running a less customized platform. Hopefully the technical challenge is moderate and a worthwhile investment.