Why did Riot lock down the API to make Season 3 rank invisible?

I thought I was imagining things, but I've confirmed that this is the case: it is no longer possible to find someone's Season 3 rank. (If I'm wrong, I will shower you with a thousand thank-yous if you can show me how to look this up.)

I'm asking because we use rank in Factions, which is organized around custom matches, to roughly compute the skill gap between the two teams. (If a bunch of Demacian Golds beat a bunch of Noxian Silvers, it doesn't seem fair that Demacia should gain, or that Noxus should lose, the usual number of points. That'd just be rewarding factions for having lots of high-ranked Summoners, and would discourage lower-ranked Summoners from participating in matches.) Right now, we're having to use only Season 4 rank, because Season 3 rank has become unavailable on LoL Nexus and such. This is a problem in cases where a Summoner was highly ranked in Season 3 but didn't play Ranked in Season 4, leading to situations where Diamonds end up counted as "Unranked" Summoners. (Our prior approach was to use the higher of Season 3 and Season 4 rank.)

So, I guess I'm wondering…is there any way whatsoever to look up someone's rank in Season 3? LoLKing does show S3 stats, but not rank itself, at least not that I've been able to find. It just seems odd that there would truly be no way to find someone's S2 or S3 rank.