I'm sure that plays into it, the official report cites creative differences. Saki herself also says she's done everything she wanted to do with the band. My biggest conceen going forward is they state their going to be a four piece yet all their present material is two guitar stuff. While a bass heavy sound is intriguing, and Hazuki is certainly capable of carrying the weight of being the lead, there's no way they can do their past catalog live.
They have another announcement on the 14th, hopefully that'll shed more light