Nice work, but I think you have to be a little bit careful about taking match-ups ratios as forward looking probabilities. Match ups lists basically tells you what the AVERAGE win ratio is at a given time. The actual win ratio varies from player to player, also there is no guarantee that the win ratio would stay the same forever.
Of course, you could put in the assumption in your analysis that all players are perfectly rational, who know everything there is to know in the game, and only make the best judgement at any given time, to make it valid. However, we all know we are not perfect, unless you work in some Ivy league econ department.
p.s. I’m a grad student too, can’t wait to join the phd fighters club!