New rating based on @clubelo site. He already has a rating system there which seems more than adequate but I was playing around with his data and decided to add drift and total elo pints gained to get a per game average. Basically if you were able to maintain a 1800 team for 10 years and not let it drift to1500 level you are credited and vice versa. Of course usual elo limitations apply; does not take into consideration players, budgets, etc. But disregarding those you can think of the number as manager’s average elo contribution per game(but don’t take it too literally). Of course the rating will change quickly for a guy like Simeone and not as fast for Wenger. Enjoy.
Here is top 20: