The current biggest factor in the way of renaming on Dreamwidth is currently the fact that the user-accessible interface to perform a rename does not exist yet. Right now all renames are done manually by staff, and I believe that to keep the volume of renames manageable, they are mostly doing this in case of typo on account creation.

I have no reason to believe that renaming would be a less popular feature on Dreamwidth than it is on LiveJournal.

I hope, when renames are implemented properly, that staff will release statistics on it (how many total and separately by personal journal and community, how many as a percentage of that type of user, maximum number of renames by one journal (or a curve of number of renames per journal, that would be even better), length of journal ownership and what point in the journal ownership the rename(s) happen, and probably more.