I kind of agree with you except that saul probably has seen tons of shit considering Walt not only barely phases him (until the end when he gets him involved) but that he is the plug. When Walt starts getting into the crazy shit it's thanks to Saul. So you definitely can't act like the greatest story of Saul's would be his side role in Breaking Bad. He could easily be involved with things just as big. I mean, Walt learned a lot from Gus and hes pretty much a part of the BCS universe even more than BB (relation to Mike and saul).
Oh yeah for sure he's been involved with Gus and company, so you can definitely get some cool exciting stuff out of that, but Walt was actually the dude who ended him (along with large part of the New Mexico drug trade) completely.
It's gonna be hard to top that.
I don't expect BCS to ever get as crazy as BB in the first place.
Its strength, in my opinion anyway, lies more in giving characters more space.
Breaking Bad was also great in that aspect, but sometimes it did sacrifice character moments for lightning fast development (can't blame them, given the reaction to Fly).