Leroux: To be fair, as tiring as the same old threads are, so are people not properly reading the OPs and jumping to conclusions. This thread is not a rant, complaint or wishful thinking, it's a perfectly valid question about the functionality of the GOG website.
The complaints in the OP is not valid or reasonable at all.
The original poster says it's "hard" to know if a game is "retro" or not, but no, it actually isn't. All he has to do is look at the Release Date near the top of any game's store page, which lists when it was originally published. So the OP is complaining about a problem that either doesn't exist, or has already been solved.
And there is no such thing as a sensible way to define what an "old" game is or isn't.
And even if there was, then should GOG waste its money paying employees constantly to monitor its whole library in order manually to move games from the "new" to "old" category once formerly-new games become "old"?
Doing things like that would be a disaster akin to the 10th Anniversary "site re-design."