#1 You don't have a clue how many people will play Hamlets unless your psychic, and also the first week, especially the first day everyone is going to WANT to try out this new content.. so your going to figure 200+ people going to be at the Hamlets doorstep wanting to try out it's content. So no this would not be able to work on a first week post 1.22 Basis! ( and this is all on based that you want this content Non-Instanced)
#2 You don't know how many NPC will be participating in the Hamlets (the Screenshot that says " Militia Survivors" says 10, that means there could very well be more then 10 NPC, since you have to keep them alive also)
#3 You don;t know how many Monsters are going to be popping out at once ( First wave 25 weak Pawns Second wave 15 mid-hard mobs, third wave 10 Hard mobs) we don;t even know whats in store with any of this.
But one thing is for certain though... you cannot sit here and tell me that only 15 players are going to show up at the Hamlets Defense..
and besides 8 ppl + 10 or more NPCs and 10+mobs at a time isn't much of a difference as 15 ppl + 10 or more NPCs and 10+mobs at a time... there isn't really much of a difference if that's what you are implying.