Always more data is useful. It's the question really of the quality of the data. You really have to make sure the numerator and denominator actually are valid to be able to make some judgment off of it. That's sometimes a challenge.
What I think I heard you say was that we need something with which, when athletes change sports, we can pick up their previous history, which can be relevant. That may actually be different from a database of all concussions.
That may be a questionnaire when the people start a new sport that asks if they have had a previous concussion. At the professional level that's what we do. We ask: Have you ever had a previous concussion? How many? When was the last one? How much time did you miss? That's useful information for us to assess and manage the risks.
I think there are two separate issues there. One is a research tool to look at incidents and the effect of treatment. Registries like that aren't always perfect data. Then the second question is how we protect athletes who go between sports.