I think a map command #nostartif (a number) would be a good idea (making nostart all provinces with fewer than x neighbours). Many mappers have tried to solve the problem with manual nostarts, but in most cases some provinces are forgoten, making the balance worse for the unlucky starting there.
If you want maps with good start locations I've made a map file with 4 neighbours mini
for Glory MP, and for cradle the last map file for dom 2 should be used, instead of the one given with dom3.