I can never compare this mod's population to the base game because any random chimp can buy mount and blade and/or napoleonic war to hop online and play for a bit, but it takes a special type of autismo chimp to go searching for and install a random mod. the total pool of possible chimps goes down significantly. Mercs, full invasion, and PW are mods so comparing those population numbers to crpg makes more sense.
I'm only able to base it off my own experience, but being a low level noob was insanely fun. Stacked odds got my dick hard as diamonds. Different mods are for different folks. I would never play full invasion or PW, but a lot of people like that gameplay which I find numbing and boring.