There should be a limit, but how many colonists/merchants/diplomats/corsars you get per year is a thing that could have no limit, or a bigger limit, like in trade, you get a extra merchant for each monopoly, but the maximum is 12 merchants per year, why not make that limit bigger, or moddable? Like 36 merchants per year, that would give you 3 merchants per month, I think Would made the game better (maybe unbalanced), as with 1 merchant per month I can't keep up with my 8 cot's, where the AI put merchants all the mouth, but I have not merhcants to send! And for colonists you receave per year, the number of colonies should have a effect in the number, representing the colonial dinamism. And the same thing to diplomats and corsars, and more you make diplomacy or piracy, more diplomats and corsars you could have.