Duncan outplayed Amare in that series. Nash, J-Rich and the rest of the team demolished their Spurs couterparts.
The other concern is laughable. Monroe is not quick footed, but he's not really slow. He's actually faster than most centers. If there's one athletic test you can count as pretty accurate its a sprint. And he tested out faster than notorious speed merchants Horford, Lopez, Cousins, Hawes, and Noah. Most of them by a pretty wide margin.
I will admit to not having seen every game of the series. However, I did see the last two games and Stoudemire and Nash ran the pick and roll down the Spurs throat. I've never see such frustration on Duncan's face before. They knew the Suns were going to run the pick and roll and they couldn't stop it.
As for the sprint drills. I put more emphasis on the agility drills because it shows whether a player has quick feet or not. Something thats important in post play both offensively and defensively. So I listed both..
Horford: Sprint - 3.37, Agility - 12.15
Monroe: Sprint - 3.35, Agility - 12.10
Aldrich: Sprint - 3.35, Agility - 11.48
Cousins: Sprint - 3.55, Agility - 11.40
Lopez: Sprint - 3.57, Agility - 12.57
Kaman: Sprint - 3.37, Agility - 11.33
Parakhouski: Sprint - 3.33, Agility - 12.07
Hawes: Sprint - 3.51, Agility - 11.88
Udoh: Sprint - 3.29, Agility - 11.15
How all that translates to the NBA game is anyone's guess. But just going on what I've seen during the season, Monroe doesn't have quick feet. I don't think that precludes him from being sucessful, but it doesn't make him particularly special either.