Late season improvement, a top caliber defense and the end of the Mark Brunell Experiment bred some hope among the faithful in the late weeks of the 2004 season, and a thorough dismantling of the playoff-bound Vikings the final week had some Redskins fans feeling renewed in their faith in Coach Gibbs. But two months into the offseason, some Redskin enthusiasts are wondering if Coach Gibbs’ best work is being undercut by another important personage:…