Surpasses - exceeds, beats, bests, outdoes, outshines, outstrips, tops. It's pretty evident what surpasses means. What you're really looking for is a set of criteria that can be applied equally to all Aikido practitioners so that when the criteria are met, or not, there will be no doubt as to who surpasses whom based on performance.
One problem is that any set of criteria you choose to implement cannot be applied to those who have passed on. Another problem is that unless your criteria can be quantified without ambiguity you must rely on judges to evaluate performance and determine the outcome. One needs only look to Olympic figure skating to see what a can of worms that route opens.
I agree with JJF that it's a question that cannot be satisfactorily answered, especially if you are trying to compare living people to dead people.
As an aside, if the question cannot be definitively answered then the claims that have appeared here on AikiWeb that there have been no to very few students of Aikido who can equal, let alone surpass the "greats", is without foundation since there are no objective criteria to base judgments on.
It's very easy to formulate concrete criteria that can be applied to the past. For example, I could say "How many teachers have surpassed Morihei Ueshiba's teaching time in countries other than Japan?". Of course, that may not be what many people are looking for.
As to being "without foundation" - well, people from different ages are compared all the time without objective criteria. It's not a yes/no question. What do you think historians do? They evaluate people in the past, many times without solidly objective criteria.