People, including me, of course expect to find the latest and gratest board games on the BGA platform, as for example, one could see how much desired the German "Agricola" was.
But I'd say, that also niche games, so games which are not well-known, are interesting for the platform. For example, I myself implemented "Bao la Kiswahili" here (currently in alpha state), a popular traditional board game in East-African countries, e.g. Tanzania, which most people might never have heard of and which will probably not gather a large player community on BGA. Still - it demonstrably got BGA some newly registered players, since an international Bao club took interest in it.
So, bottom line, I think that additionally to the mainstream board games, also niche games have their eligibility on the BGA platform and should be supported and promoted.
But I'd say, that also niche games, so games which are not well-known, are interesting for the platform. For example, I myself implemented "Bao la Kiswahili" here (currently in alpha state), a popular traditional board game in East-African countries, e.g. Tanzania, which most people might never have heard of and which will probably not gather a large player community on BGA. Still - it demonstrably got BGA some newly registered players, since an international Bao club took interest in it.
So, bottom line, I think that additionally to the mainstream board games, also niche games have their eligibility on the BGA platform and should be supported and promoted.