“Gladiator II” isn’t quite the prestige film the first one, a best-picture winner, was in 2001. It’s more a swaggering, sword-and-sandal epic that prizes the need to entertain above all else. No one in “Gladiator II” understands that more than Denzel Washington. His performance as the Machiavellian power broker Macrinus is a delicious blur of robes and grins – so compellingly over-the-top that he nearly reaches 1990s Al Pacino standards.