The critics could have gotten over the fact that The Joker wasn't in the goddamn movie would have been a start!
Would've been nice, but it's a testament to how good Ledger's Joker and by extension the mark that TDK left that critics were still thinking about them. Of course, it's rather unfortunate they couldn't get over the fact that Joker wasn't in the movie and TDKR wasn't TDK, but it's also to be expected when you actually do a follow-up to TDK.
It may be a limit of the character himself but do you think there is anything either hardy or the creators could have done whereby the bane performance would have been seen to be on par with that of ledgers for the joker?
As in hardy being seen as a shoe in for a best supporting actor nom like ledger or bane going down as one of the great cinematic villains.
Hardy did great, I thought his performance was really good, embodying everything Bane is about. The creators did fine as well, appearance-wise I thought this version of Bane was more visually appealing than his comic-book counterpart, and especially compared to his most recent appearances in DC animation and the Arkham games. The choice for his voice was bold as well, it was definitely not your typical big-guy voice and I thought that was interesting. It certainly gave this version of Bane a very distinctive touch.
You're also correct in saying that the character is limited in a sense in that he's known for breaking Batman's back and was created for that singular purpose. This is where I thought the creators could've come in...his association with the LoS was a good start I think, as was his excommunication by them. But I think there was room for improvement: for one, even though I'm not one of the ones that believe he was Talia's lackey, I still would've preferred for him to be working independently and to have founded his own distinctive branch of 'LoSers'. While I enjoyed the story between him and Talia, I think having him as a true revolutionary would've been more compelling. The class warfare between the citizens of Gotham was one of the more interesting aspects for me going into this movie, and I was rather disappointed that it wasn't handled a bit differently. I thought there was some real potential for Bane to be this charismatic, revolutionary leader, certainly that flashback of Gordon at the beginning of the movie in which he says "And it will be a very long time before someone inspires us the way he did" seemed to indicate as much, at least to me (of course, it was a reference to Bruce/Batman as well).
In this scenario, Miranda/Talia would be this supremely talented infiltrator that would be operating under the noses of both Bruce and Bane (admittedly, this is an idea I borrowed from another poster on these forums, namely
Fenrir), working towards achieving her father's goal of destroying Gotham. Of course, for this to work better, I think Talia should've had a part in BB as well, but that's another story. The bomb would be used as a true insurance policy by Bane and his forces against the government, while Bane would rule Gotham as its 'king'. Talia's intentions towards the bomb from the movie would be maintained.
All this is not to say I didn't enjoy Bane as a villain, he's probably my second favorite villain in the trilogy, but I just think there was more untapped potential for him in this movie. Just my two cents.