Re: In hindsight what changes would you do
A couple things..
The Riddler - I feel like he would end up being compared to Joker much more than even Bane is as well as being nothing really new after seeing Joker in TDK.
John Blake - I think it would be best to not even mention him if someone had a different idea for TDKR because Kevin Smith made a great point that the eight year gap could've been there to also grow the character of Blake who was mostly living in the orphanage during those eight years. He is a rookie after all and could be as young as 20 in TDKR.