I would like to be able to see the error ratings when I'm in the "Roster/Manager Profile" window...
You might want to check out sposfan's page with modified managerial profile windows. Mine has expanded defensive ratings, but only shows replay batting and pitching stats (no real life stats) so that might not suit your purposes. But it looks like DZanr's version also includes expanded defensive ratings while still including both real life and replay stats.