Our team will have a look at this, but the fix is not simple, because the logic of creating a fundraiser also creates a WordPress user, and much of the "under the hood" functionality of the Peer-to-Peer add-on is reliant on that logic.
The good news is that in the next version of Peer-to-Peer (in final testing for release soon) there is a mechanism for site admins to create fundraisers in the back end of the site, and so in the event of a typo, the admin could create a new user/fundraiser and assign the donations to the new user.
This feature (the fundraiser being able to change it themselves) is not likely to be developed. It's more likely that we'd add the ability for site admins to change them on the back end. Either way, we'll have a look!