@Riot: Why is LoL Nexus missing previous rank information? Is S4 rank info in the API?

Here's what LoL Nexus used to look like: http://i.imgur.com/D4D1Fbw.png

Here's what it looks like now: http://i.imgur.com/x1kbv7J.png

During Season 4, LoL Nexus abruptly stopped displaying S3 rank alongside S4 rank. I asked why, and I believe Sargonas explained that it was an unintended side effect of some changes to their API: that they overwrote the S3 rank data with S4 rank data. I think Sargonas indicated, though, that going forward both S5 and S4 data would be available.

But it doesn't seem like that's the case. I haven't yet spent the time to work through Riot's API and figure out how to pull up this data, but given that LoL Nexus is still showing only current season data (now Season 5), I'm assuming it's not available. But then, LoLKing seems to have access to this data...though perhaps only in archived form.

I don't understand. Before, it sounded like this was all a technical mixup. Now, it's starting to seem that Riot has taken an official stance against making previous seasons' rank info available through the API.

Could we get some clarification?

As for why it's relevant: I run Factions, and long story short we use rank info to help balance tournaments. Our preferred method is to use the higher of a person's current or previous rank. For instance, if someone is unranked in Season 5, but was Platinum in Season 4, we would count them as Platinum for balancing purposes. The problem is that it's getting really hard to find this data. Doing it for individual Summoners is certainly possible, but when you need to score hundreds of matches, it's dramatically easier if you can give the scorers a single screenshot that shows everyone's S5 and S4 rank.