it is very easy to train pioneer

before the AI could expand i can occupy large part of the world - if i want, but i don't wont, because then there is no point to play

solution: pioneer needs a lot of money, material, and at least 30 population (and on harder difficulties AI needs are lower)

- so all settlement begins with 30 population and can't be less

- you need at least 60 population in a settlement to train pioneer

and you can't go under the actual settlement level, because that is the core population, who don't want to move

or you lose the effects of the buildings until you rich the certain level again

or anything

this case the level up of settlements must be a bit higher