I use 2d8 zombies as a ‘go to’ example for many situations. I idea is that 2 zombies is likely a pushover for most parties, 16 zombies is a likely TPK. In Rolemaster superior numbers can swing any battle.
My problem with 2d8 zombies is that it implies a carelessness about the encounter and the adventure. It suggests that no forethought went into the encounter.
If the encounter is a simple device to use up PP, healing or ammunition, then the GM should be scaling the encounter to be a specific level of threat. Too much and the characters may not make it to the BBEG. Too little and the encounter doesn’t do what the GM wanted.
That is what I normally think when I see adventures, probably converted from D&D or PF for use with Rolemaster.
But, what if you go with the randon ‘No. Appearing’?
Does every encounter need to be solvable? If there are 16 zombies this time, shouldn’t the party be thinking about a different approach rather than drawing blades and wading in?
If they met 2 zombies last time, and 3 zombies the time before that, they may well rush in, expecting there to be small numbers again, only to have to re-evaluate and extract themselves when they find out the true size of the force against them.
Does every encounter need to be solvable? That is a populat discussion in its own right.
My players would rather avoid than confront. This makes them rather easy to manipulate. You just put an obvious threat in the places you don’t want them to go, and they would rather not confront it.
Put an obvious threat in all directions and they have to do their little risk assessments to choose how best to ‘win’. They are obsessed with winning, this is not a group that are satisfied with staggering away with 1 #hit and a hard won victory. No, these guys want to walk away without a hair out of place.
They want to save the world, but doing it while well dressed and looking presentable.
I still think that rolling No. Appearing at the game table is not a good thing. If you roll it during GM prep, and then use the result to shape the encounter, or add meaning to it, then that is good.
The biggest gain I think could be that having an unexpectedly hard encounter may go counter to what you may normally choose to do. If the players are used to a few warm up battles, maybe increasing in severity as they get further in to the adventure, then random strengths of foes could throw them off balance.
This goes completely against my normal way of balancing encounter.