I agree, they've tried to do both strategies at the same time - they either need a longer history or to drop far more than they have. I'm not thrilled that they dropped the JLI - since the success of a new one seems entirely linked with nostalgia for the old one - but it makes sense given where the conpany wants to go.
As for Jason Todd, snce they've kept Batman mostly intact, there would be a Jason Todd-sized hole in there which would be hard to explain. His history does imply that Batman took a terrible oath never to have a Robin again after Todd died, a terrible oath that lasted ... a month? Two?