Spambastard, do you mean before or after the preliminary patch notes get released?
There are few examples indeed about changes being done after we bring the patch to the test dimension. However, what goes into the patch in the first place is based almost solely on the community (and Community; not sure whethere you meant the players or the team).
Recent examples of changes made due to player feedback after patch notes went out: Dying penalties (what level they kick in at) and Grid Armor modifiers (added due to feedback on the new wear requirements), both in 14.2.1.