Geezers need excitement. And for two of them, Redskins quarterback Mark Brunell and former Redskin/now-Viking QB Brad Johnson, ESPN’s Monday Night Football premiere will be providing it as these two NFC foes duke it out at FedEx Field tonight at 7:30 p.m. For Washington, who miffed and mussed and stunk their way through the preseason, all eyes will be on the offense. Widely deemed a depthless liability toward the end of last year, a heavy…