Did ask about this (Diablo II) but nobody's probably going to reply and that's ok.
I just think expansions, DLCs or add-ons should be differentiated better from the game's main release - if those are also considered as releases which belong to the main game's page and not separate product pages. To be clear, only if the content itself is officially advertised as such (exp/dlc/add-on). So two things come to mind: a second option when adding releases of the game: first is obviously the existing 'release' and the second one could be 'release - expansion/dlc/add-on'. Other thing would be assigning different color coding for it (probably another shade of blue) because, in all honesty, if one looks at the releases, there is no certain way to know what they exactly are because it's all the same color:
And if one actually clicks on the exp/dlc/add-on it'll open new page with 'exp/dlc/add-on' in the brackets instead of the usual 'game', simple thing like this:
Oh yeah, expansions/dlc/add-ons releases would be created only if they have album entry to associate with of course.
There are some games (with product pages) that should already benefit from this - Final Fantasy XI, Mass Effect 2 (which has album entries with music specific only for some of its DLCs - Lair of the Shadow Broker, Kasumi's Stolen Memory, Overlord), Diablo II and World of Warcraft which has its expansions here with separate pages instead of them being just the releases of the main game. I'll leave special cases on the side I guess, like Guild Wars games which aren't clearly advertised as expansions, that's why I mentioned the advertising stuff a bit earlier (obviously not talking about Guild Wars 2
& 3 <-- oops).
This is just a proposition of course, nothing more; I'm interested in hearing other members' opinion about it (if any).