I always assumed (given Batman's firm "No killing" rule) that none of the plans used were Bruce's plans fresh out of the drawer, but ALL of them warped to lethal level by Ra's own genius and mindset. Bruce, being who he is, WOULD take responsibility for them because they ARE based on his plans, but they're not exactly as he would have implemented them.
And I still hold that Diana and Arthur voting against Batman (for the reasons given) is the height of absurdity. Neither of them are naive, both are trained warriors and leaders, and if they can't see the inherent stupidity of "We wouldn't have minded that you had these secret plans to take us down if you'd told us you had them" which completely defeats the point of them being, y'know, SECRET" then frankly they shouldn't be in the League