Re: In hindsight what changes would you do - Part 1
And speaking of Bruce's paranoia, it's not like he just trusts Dent to be his successor right off the bat. He asks Gordon if he trusts him, then in the next scene we see Bruce in the bat-bunker watching some video footage of Dent. Alfred mentions to him that he's pretty much legit, yet Bruce says that he is watching him; closely, to see if he can be trusted. It's not until he has dinner with Dent, Rachel and Natasha, that Bruce starts to believe in the Harvey Dent hype.
Then Bruce reassigned R&D without even telling Lucius. And when Fox asks him, Bruce tells him that he's playing this one close to the chest.
So yeah, I think he was plenty paranoid and non the less crime fighter-savvy in TDK.