Originally Posted by
Little_Mac
The toughest part of it would be the detective and psychology work. It's a much tougher issue to match wits with the Riddler, then think terrorism aka Ra Al Ghul/Poison Ivy, then figure out an insane person like the Joker. It's no use beating up the bad guys if you can't even FIND them nor get to them on time.
The issue with Stark would be the limitation on upgrading technology. He is stuck with the current Bat-suit and technology. Do you really think that he can swing between buildings using the Bat-Grapple? Which villain is Tony Stark beating in hand-to-hand combat? Joker, Harley Quinn, Killer Croc? The Bat-suit doesn't have THAT much protection on it. Also, since Stark is limited to Batman's tech base, the various villains can HACK the drones and robots if Stark goes for that option. If Ra Al Ghul can break into the Batcave multiple times, he is able to hack the software since Stark CAN'T improve on it (as stated by the OP).
The easy answers are Green Arrow and Superman. GA does 90% of it already. Superman uses his journalism background to handle the crime solving and he has picked up enough H2H combat to be able to handle himself.