Merging misspelled artists, albums and tracks is not possible at the moment, because fixing this affords a new scrobble database first which is being currently worked on. For now you can vote on the wrong and the correct page that the name is incorrect/correct.
A possible solution would be the introduction of a personal clone library. Personal clone library(PCL) is a clone editable version of the user's library. PCL should not have any impact to the catalogue database and it is for personal use only.