Hello JetBrains TeamCity team!
You've asked for dream features in the dev blog (http://teamcitydev.blogspot.com/2012/05/teamcity-703-bugfix-fixes-and.html). If I absolutely had to pick one: http://youtrack.jetbrains.com/issue/TW-5884. It has 32 voters over the past 3 years. The lack of this feature complicates TeamCity management to the point where we have to create new projects just to take away permissions from some users that should not run a particular build or see the changes. We've been waiting for this foreveeeeeeeeeer.