We had customers that wanted 'permissions' for their "sub" accounts so they could have fine grained access to features. They would threaten to not use our system until this was implemented.
Implementing this feature was a lower priority and more difficult to implement for us then other revenue generating features (also a good way to prioritize things).
The interesting bit is they still used our system, despite the missing feature. I think because we focused on things that generated revenue. We kept good conversations with our customers and let them know when we thought we would add it. We kept delaying it and it took us 6+ months. In the meantime, we increased our (and their) revenues the whole time.
Once we finally rolled out the feature, existing users didn't really care and new customers just had the feature. This strategy worked really well a number of times.