Oh, yeah? Who is the Roman Emperor these days? Who sacked Rome? I know they weren't exactly the "Barbarian Hordes", but they were warriors.
Are you content to make this a pissing contest? That the Roman's failed to maintain their military prowess says nothing to the validity of the principles they established. Most of those principles are still valid to this day, though like camoflage uniforms, they've been incorporated into nearly all modern military organizations.