This question is related to my other question, but also this entropy calculation question as well as this article about PBKDF2. It may also be considered as a duplicate of this question, although in our current case the password's entropy isn't as high.
If a low iteration count is used, it can allow for fast brute-forcing, but what if the entropy of the password is high enough (50 bits? 100bits? more?)? Would it still matter this much?
Would there even be a way of determining a minimum entropy?
A limited charset like "0123456789ABCD" would surely hinder reaching high levels of entropy, but given a long enough length, it's rather hard for me to guess if it could still be considered safe or not.