If the Packers can stay healthy, play pissed (or in other words give great effort every single play) and play smart then I'm sure they can compete with almost any team in the NFL.
Am I sure they can stay healthy? No... that's anybody guess...
As far as giving great effort I'm not sure... I'm sorry but Clifton and Grant seem to go half speed sometimes...
I remember a play against the Vikings last year where the OL made a great hole and Pat Williams was knocked on the ground with a Packers OL on top of him but he was able to reach out for a VERY POOR arm tackle attempt and amazingly some how it work... and on a play where Grant got 3 or 4 yards when he should of had at least 10 yards and most likely would of had about 15... but he wasn't running hard and a very poor arm tackle took him down didn't get the first down and pumped up the Vikings defense with excitement and get the Packers upset with disappointment...
As for smart it seems like the play calling starts to repeat it self sometimes... and two years ago with Grants injury it seemed like every time Grant was in the game it was a running play and you better bet the defense noticed it since the public noticed that as well.
But yes I think they have the pure talent to compete with anyone... just not sure they can stay healthy, give full effort when it's needed and always play smart...