We have a similar problem in our studio - many people just come for fun and don't take their dancing as seriously as I do, they don't practice between classes and don't pick things up very quickly when we learn a new step. That holds back the people who are ready to advance. Unfortunately, it's a small city with not very many options - e.g. privates, or moving to a different studio - so we all have to accomodate each others' goals and try and make the best of it. I have heard that people who don't do competitions and medal tests get annoyed with the focus that our teacher places on exam routines and technique in the weeks approaching exam time - guess you can't please all the people all the time, right?
I have to agree with everyone on the partner issue...sure there are lots of people I dance with regularly but only socially. Id love to have a regular practice partner!