Indeed it is. Miranda will still be a force, and certainly someone fans will want to pay to see. It's just pretty clear now that he's just a step below the top guys, which is OK. He can still make a mark on the sport. Not everybody can be Ali, some have to be Leon Spinks!
Not just his defense, his overall technique sucks. He can't fight going backwards, as Pavlik proved. Pavlik was the meat slicer to Patera's balogna in their fight. Tonight, AA just smoked him with those solid shots after the rope a dope act in the first couple of rounds.
Very good fight for Froch to make though. Miranda will be looking for a payday and Froch will be looking to break on to the world scene.
Miranda has always just been an entertaining fighter with a good punch. It's now clear to everyone (if it wasn't already) that he doesn't have what it takes to beat the top guys from 160-168. If he still thinks he can, he better make some serious defensive adjustments in order to protect that shaky chin of his. If i were him I'd take a tune-up against a can, then look to get a fight with a fringe contender, eg: Pascal. He should avoid big punchers.
I think Miranda is nothing more than a gate keeper. He will always come up short against opponents with a pulse and would just beat a bunch of soft punching journeymen like David Banks.