Of the 4 major tournaments, historically, which one by winning it, best determines which players will be great?

Currently all four grand slams require very distinct skills.

Australian Open require superior fitness due to heat.

French Open requires superior groundstrokes to sustain long rallies.

Wimbledon requires great strength and power to cope with fast skidding balls.

US Open requires great mental fortitude to deal with distractions, and daily changing wind and weather patterns.

You need all of these skills to be truly great. If I had to choose one to determine a great player I would chose US Open because as everyone knows, being mentally tough is the most important thing for a tennis player.

Great question.

Of al 4 major grand slams, Wimbledon still remainsmost competitive and prestigious not only for professional players but also for world wide spectators , due to its unique seeding system , unpredictable climate forcing players to participate on the same during rain fall and also same day to be engaged for a singles or doubles or mixed doubles without any respite , testing ability of endurance , stamina to withstand , high humidity , cloudy weather etc puts players on acid test

For many tennis players, Wimbledon is the one to conquer. I can't tell you why exactly but I hear them say it all the time.

i think all 4 are considered equally prestigious. in purely tennis terms, they are all equally important (the all have equal ranking points for example), but some think wimbledon is the most important because of its history.