I donßt know if it has been asked elsewhere, but why does BGG not link from the base games to all the expansions? Sample:
HoW Basic http://www.boardgamegeek.com/game/8134
HoW Italien http://www.boardgamegeek.com/game/21781
HoW Russland http://www.boardgamegeek.com/game/21782
HoW Pacific http://www.boardgamegeek.com/game/20409
HoW Fall Gelb http://www.boardgamegeek.com/game/21783
In the base game entry you can´t find any link to all those expansions. So when you are keen on a game and find it at BGG you won´t be able to know that there are any expansions - which really often changes ones interest in a game. HoW without expansions is not playing as well as with those expansions. A new player, interested in this game would only read the comments in the base game entry and could be disappointed - but if he could find anything about the expansions his opinion might change a lot.
Another example would be DOOM: The Boardgame. The base game is ... nice. But nothing more - has some balance problems which hurt the game fun a lot. The expansion really changes the whole game play, improves it a lot and makes it a very good game.
Same with Runebound: Second Edition. This game pulls much of its long-time-fun out of the expansions. And there are a lot of them. But neither in the main game entry nor in the expanion entries you can find any links to each other.
I would strongly recommend that base games link on their expansions. If they don´t - you always need to re-enter the names into the search engine and try to differ the expansions from other games that only sound similiar and don´t relate to the searched game.
We have "you might also enjoy" - why don´t we have "expansions for this base game" right over this one?
From what I understand, this is on the to-do-list. The expansionpages are due for a revision. This is a big operation, so it'll take time probably. But as far as I know, they'll get to it at one point. There's a long list of things-to-do.
This used to be the case.
Linked items were demarked as 'sibling', 'parent' and 'child'.
Users voted on the relevance of each linked item (is it really a 'sibling'?).
Anyone could add a missing item (C&K missing from SoC? No problem, just add it).
This was an excellent feature and needs to come back in some form.