I don't think we have data pointing to the fact that reinfection is worse. I think we have data pointing to the fact that second round is just as much of a crapshoot as the first round.
I don't think there have been enough cases of reinfection to claim we have any usable data on the subject. There are many variables to parse in order to even start. Were both infections the same strain? What symptoms were experienced the first time? The second time? How were the infections transmitted? How prevalent was the virus in the locales of transmission? (Last 2 questions go towards amount of viral load each person was exposed to.) How early were symptoms noticed? Treated?
I'm by no means a science/medical person, but these are questions I have off the top of my head that I think change any study into reinfections being better/easier or worse/harder.
ETA: time between infections, lingering complications from the first infection, any medical issues between infections - all additional factors. There have to be 100 other factors I'm not thinking of.