There are applications where it is useful to get the rank without counting all the duplicated entries with the same score, for instance in a game leader board if I've the best score, even if there are other three with the same score, I'm supposed to be the first.

The feature was already implemented here:

https://github.com/Sylvain-Royer/redis/tree/unique_ties

It was also discussed in the mailing list. The new function is quite useful and the code not too complex, so I'll re-evaluate it at some time in the future as the code gets more tested.