CO2 wrote...
It's literally one button press away.
Well, let's count, shall we? We will start from the Front page -> manga's main page -> "Read online" -> access drop-down list -> thumbs. That's four clicks. When it used to be two: Front page -> manga's main page -> (whatever the link was to get to the thumbnail page). Definitely more cumbersome.
While I admit it was a bit un-intuitive to land either on the cover/first page or the thumbnails page, depending on where you clicked on the manga's main page, it still makes a lot more sense to be able to access the thumbnails directly. After all, we already see the cover of the manga on the front page, then a second time on the manga's main page (this time a little bigger) and then a THIRD time, now in full size, when you click on it.
The RELEVANT info would be to see the thumbnails, so as to quickly judge how long the manga is and how well (and in what style) it is drawn. The cover is just a cover - usually a fancy picture, but it tells next to nothing about the actual content.