M2TW lets you adjust the population levels for settlements (i don't think RTW did) which is a nice start. You can also adjust the various contributing factors which effect population growth from how much each level or farming gives, squalor and chivalry etc.

MT2W doesn't have slaves (as far as I know) and it doesn't allow for unit disbanding.

I'm sure the EB can do something about slaves by adding traits to governments when a settlement is enslave.

I've always found that population growth in M2TW is too fast and you can easily cap out a settlement within 100 years, with settlements being ready to upgrade almost a few turns after you finish building the last settlement upgrade.