Comments like this just show how futile it is to have a decent discussion with some some people.
You honestly have doubts about Schumacher being tier one, that's bizzare.
Yes I do.
Firstly, consider his opposition; his closest challenger for a while was Coulthard.
Secondly, consider his team-mates; Herbert with smashed ankles, Barrichello who was beaten nearly as convincingly by Button, Massa and Irvine, nuff said.
Thirdly, consider the legislative background in which he raced; Ferrari vetoing all opposition, Benetton running illegal software.
Fourthly, consider Schumacher's own self-analysis. He was sufficiently insecure to cheat to win titles. Got away with it once.
And fifthly, look behind the stats and look at the state of GP racing. Identikit tracks, and in the Schumacher era identikit races. Go harry flatters for a quarter of the race, stop, repeat, stop, repeat. Car management was down to a minimum. The sport had changed for his second coming and he was nowhere. Can't use the lay-off as an excuse - Lauda left the Cosworth era, came back to the turbo, and kept Prost honest.
One of the reasons why we can be sure that Fangio, Clark et al were great was because they raced on the original flat-outs of Spa and Monza, the herky-jerk of Silverstone and Aintree, the funambulism of Monaco and Pau, the sheer insanity of the old Ring and Solitude. And won on them all. The Tilkedromes might as well be the same track over and over again. They also won in other things as well (Fangio in rallies, Clark in Indycar and touring cars). And if you wanted to challenge Fangio in his 250F, you could go out and buy a 250F. No excuses.