I only consider gameplay data from players who have at least 1 win already, specifically because new players would have an outsized impact on winrates. However, the Warrior is the first character to unlock, so considering only newer players actually tanks his winrate the strongest, as absolute newbies have him as the only option.

You'd also be surprised about the number of runs in total. I won't give away specifics, but even when only considering 0-chal runs from people with 1+ wins it's on the order of thousands of runs a day. I actually specifically ignore runs from higher chals because at that stage the number of runs becomes too few to make meaningful inferences.