Hmm, sounds like the whole contract might've been re-negotiated then. Which is probably good for Toei too, as whatever price was set back in the mid-ninties must be a pittance now due to inflation. And from Saban's point of view, I believe they had two years from a Sentai series concluding to confirm they were adapting it, but given that they've only just started airing Super Megaforce they're basically three years behind. So they're having to commit to buying the Sentai footage only to leave it on a shelf for at least another year. I can also understand that Bandai will be keen to get straight to continuing an extremely profitable toyline overseas rather than having to struggle with the less popular Go-Buster toys instead, so it's good business for them too.
I agree it's probably the Bandai factor that was crucial though. Problems with story or characterisation could always have be sorted in the adaptation process. It would have been nice to have had a mini-series or TV movie of the Go-Busters though, just to slot it in there without having to keep it for a year.
The next question of course, is what elements will they drag into Kyoryuger (assuming that wasn't code for "we'll just use the Go-Bus Vs Kyoryu movie bits that involved the other two dino sentai bwahaha!"). And will they continue to use casts for two years, given that the next lot would therefore be dinosaurs that 'upgrade' to trains?