Don't listen to them, this cheap trick won't fly in Perisno, especially in 0.9.
Your army of peasants will be obliterated with minimum losses on the enemy's side (both in real fight and in autocalc) because quantity without quality now benefits your enemies more than it does you.
And from the perspective of cost efficiency trash units are better only when your leadership is low. 1 coin is 1 coin and will always be while top-tier troops' wages will decrease drastically as your leadership increases.
Also... 1000 peasants? The average castle garrison strength is 3k-4k, the average town garrison strength is 7k+, autocalc strength of an average tier 1 soldier is less than 1 rounded up to 1. So you need more like 4000 peasants - 10000 peasants. Good luck collecting them.
You want strong garrison? Pick troops with high tactics and intelligence and low charisma. The first 2 stats affect their autocalc strength in Perisno, the last one affects their upkeep.
The troops from Maccavia, Hakkon, Cretas, TTL and Kaikoth are most tactical ones, elves are the smartest ones.
Pick preferably archers and infantry (their autocalc str is bigger in sieges, especially archers').
How good are champion gladiators? are they worth the time and money to get them or is it better to just get swordsmen and northguards?