What I found particularly odd was that Bane never used venom to enhance himself or any of that, when that's pretty much the central aspect of the character; his power, his weak nature that drives him to "prove" himself by beating Batman, his battles with addiction, all of it.
I've heard claims that it wouldn't fit in Nolan's more realistic adaptation, but why not? Venom isn't magical in nature, it's not an alien substance or the jizz of a dead Lovecraftian god. It's just a chemical compound with some funky properties, much like Scarecrow's fear gas in the first movie. How does that break the gritty realism angle?
Also, it would have given us a way more awesome third act if they'd switched the venom story around (in the comics, Batman became an addict first to enhance his power, and then broke the addiction when he realised what it was doing to him) to Batman powering-up on the stuff in order to defeat Bane, and then the whole learning-to-be-Batman-again angle could have worked the second time as him weaning himself off an addictive and dangerous drug. Then you could make Talia more impressive as a last-act twist villain, with some plotline about how she'd engineered the whole thing somehow.