As I understand it, regulation means the landing price at STN is set as is the case at LHR & LGW.
If arguably Stansteds low cost competitor airports are SEN & LTN then how is regulation a good thing for STN? Part of the reason EZY have moved to SEN is precisely because SEN can undercut on price. Regulation is designed to prevent the alleged "big boys" from riding roughshod over the alleged (no offence meant LTN/SEN!) smaller airports.
New owners will almost certainly have the capacity to cut costs & other inhouse charges as LGW have done, but regulation from their point of view will curtail how much room they have for manoeuvre.