Well, outposts costing the same as a settlement is stupid imo. (a settlement is far more worth it than an outpost) Maybe they should remove the outpost thingie from pioneers, and let sovereigns and governor champions be able to found them instead with maybe a CD? Would make more sense, and make you able to tweak pioneer costs a bit.
Good point - kind of like the pioneer/explorer and settler concept. Current pioneers (maybe slightly cheaper) for outposts, and I still like this idea for settlers.
Each city ALWAYS has people that want to migrate, so there is ALWAYS a non-rushable pioneer building that is worth X (say 20) pop.
Once completed it becomes a stationed unit.
Each city can only have 1 active at a time and production of the next does not commence while the pioneer is active.
Pioneer production does not affect city production, its essentially a separate function
Pioneers can be consumed by another (or the same) city to increase population
So there would be constant steady expansion for all civs, the further you are expanding the longer before you can build another.
Possibly have techs (path of governor) that modify this slow/speed up, etc - expansionist as a sov trait, etc
Also adds options for getting that key city to level 5 - do not expand to more cities, grow existing ones - specifically say you are fighting 2 fronts, clear one up and have a fortress on the other front you can attempt to level it up with pioneers from the other front.