OAKLAND -- Of course, a million times of course, a preseason pep rally should be full of optimism.But Sunday's Raider Nation Celebration outside of the Coliseum which drew an estimated crowd of 7,500, including Oakland Mayor Jean Quan, also had a dose of angst. A year has yet to pass since Al Davis passed away so this new era and regime has many fans just as excited as they are anxious about what general manager Reggie McKenzie and coach Dennis Allen are bringing to Oakland, under the watchful eye of Mark Davis."I've been gone too long," McKenzie, who played for the L.A. Raiders from 1985-88, told the crowd, whipping it into a frenzy. "I'm back with the real team."A shot at the Green Bay Packers, for whom he worked since 1994? Hardly. What else is he supposed to say?The rest of the afternoon had just as many feel-good moments from the Raiders. A sampling, then:Shane Lechler: "Though Al isn't with us anymore, we're going to carry on the commitment to excellence."Khalif Barnes: "We need you (the fans) like ebony needs ivory."Allen: "We're going to put a product on the field, Raider Nation, that you'll be proud of."It starts with Monday night's exhibition opener against Dallas.