This idea came up a few times here on the suggestion forum (example
https://mangadex.org/thread/56423) and I want to support it as well.
Some people simply don't check their progress in the manga and blindly click on the direct link from their homepage or follow list. While it is their responsibility, this should be a good QoL change to catch the ones falling through the system. Below is my brainstorm:
1. Have a warning dialogue even when clicking the chapter from outside (and not just from the reader).
Similar to the warning we get if we read the next chapter that skipped more than 1 chapter ahead. MD should check if the new chapter is more than +1 of the chapter before it on MD. If so, issue a warning. This should not depend on whether the reader has read the last chapter on MD; the warning only cares if the new chapter is more than (previous chapter on MD +1).
2. Disable direct chapter link from Follow and frontpage.
This is something I personally do, and believe everyone should do as well. Clicking on the manga and then on the chapter ensures that you see the new chapters vs the old chapters you read, and whether if it skips anything.
However, since the practice of clicking on new chapters from follow/frontpage has been fairly common, this might be a downgrade to people who never experience the possibility that their chapter might be skipped. If so, they won't see this as an improvement and only as a bothersome function, possibly turning them away from MD.
2.1. Have a "NEW" tag on the chapters when clicked on the manga.
Related to #2, if you are to only click on the manga THEN search for the new chapters, it could be quite hard to do so. Personally, whenever I see a new title on the updated front page, I usually click on the manga before noticing what chapters were new. If said manga have 200+ chapters, I'll have to scroll around and search for chapters updated in the last few hours. Note that new chapters aren't always the latest chapters; it could be a special between ch.30 and 31 three years ago, or another scanlator group reuploading chapter 1.
To solve the hassle, a "NEW" tag could be considered. It will work like the "END" tag when the chapter is the ending of the series, but instead of it being determined when uploaded by the scanlator, this "NEW" tag will be automatic for chapters that are uploaded to MD in the last x hours. After x hours, it will disappear. The point of this tag is so that when scrolling, it is easier to see which chapters are new, therefore saving some time to look at the "Age" section.
2.2. A different tag can also be used instead of "NEW", while following similar mechanics as 2.1.
For example, a green circle:
When read, the circle will turns into an eye to mark as Read. The eye can have a higher priority, therefore if a chapter is read, the eye is shown instead of a circle.
Just some brainstorming.
EDIT: I kinda notice how useless 2.1. and 2.2. are since the color-coded "1hr ago" serves this same purpose. I guess my points are redundant.