I agree the Jedi seem to lead to a lot of bad things happening. Many evildoing Darths seem to be ex-Jedi, and at least in the case of Darth Vader the screw ups of the Jedi played a large role in leading them to the Dark Side.
Something's rotten at the heart of the Jedi order, I think that's what Luke discovered in the first Jedi temple. My speculation is Snoke is ancient and he was present at the first Jedi temple, he was one of the first Jedi, maybe the very first who chose to cross over to the Dark Side. Maybe he isn't alive but a force ghost.
As for the solution being a mix of the Light Side and the Dark side, I hope they don't go that way, it seems silly to me and wrong philosophically. A mix between good and bad intentions and deeds does not lead to a more balanced mind.