Sounds like you ran into a bad "not invented here" culture, which can seriously slow down a product. Even worse, they are often so passionate about the tech that they can scare management into agreement with their priorities. Kudos to you for having the backbone to stand up and fix it!! Also: I am no fan of Spring ;) -- I just have ptsd from the early xml config days. If it were already in place though, I'd roll with it.
Sounds great but I was expecting more evidence. They talk about this shuffling method, which interleaves material as a way to provide spacing and reintroduce material. But it appears to just be their opinion that it will help improve retention. Also what is the deal with this "hypothetical interaction between ISI and RI"? Why not do enough experiments to actually plot it out? Anyone can graph out a hypothetical interaction.