Re: Just my 2 cents.
You mean aside from unleashing the Amazo on Bruce and Dick? Okay, how about in the Bruce Jones run on Nightwing OYL, they fight repeatedly, and Jason wants Dick out of the way so HE can be Nightwing.
And I'd say, and always have said, that Bruce IS sane, Bruce is ridiculously, painfully, agonisingly sane. He's possibly the sanest person on the planet. Obsessive yes, but sane. He has no illusions about his missions, he can't afford them. He is, in Pratchett speak, perpetually knurd.
Jason's willingness to kill IS what makes the difference IMHO. He ran around Gotham leaving bullet ridden bodies in his way, stringing the bodies up as a lesson to the rest.