@Aazalot, I think some of the complaint regarding the test was that it was a test yet had a pretty significant RP impact. If anything, being a test (and especially a first test) I would probably tone the consequences of the losing side to a "This asset was heavily damaged and needs to be repaired" -> "New Event Triggered". Then, on a potential 2nd siege event (3rd event in all), have loss resulting in its destruction or success result potentially putting things back the way they were.
Save the "This asset is lost completely" consequence of losing for when the siege isn't a test of some new changes.