I've seen that the rider comment is used only for doping issues, normally. But I think it could be interesting to add information about great injuries of the rider too, in order to understand better why any rider has a worst year compared with the rest of his career.
For example, if you look Coen Vermeltfoort's profile and you haven't got information about U23 riders you could think: "Wow! Why this young talent has 0 CQ-points in 2009 after an impressive 2008?". So, if there's a comment which says he had been injuried or ill, you understand the reason of his strange CQ-value graphic progression.