Test report: we were playing for over 2 hours on our server and we could not find any game breaking bugs. The multiplier was being applied correctly. (XP was disabled though)
Two Three suggestions: 1. Remove the item screen after the end of a round as you cannot "respawn" even if you switch gear. 2. Replenish ammunition for archers, crossbowmen and throwers after winning a round. 3. Make flag carriers unable to use horses or slow them down a lot.
Looking forward to seeing XP enabled, was great fun.