Louis XXIV
Le Roi Soleil
First off, these aren't going to be Civ4 vassals and colonies. The goal is to start fresh and add a feature that is designed to play well with Civ5's features while still having a relationship to the historical thing of its name. I'm not reinventing the wheel, so these ideas are actually tweaks of current features, but I hope they would give excellent opportunities for new play strategies.
Colonies
Colonies are pretty straight forward to implement. The biggest thing about a colony in Civ4 was that you did not directly control them, but they contributed towards your civilization. In Civ4, they were essentially self-created vassal states. However, in Civ5, the most obvious analogy are Puppet Cities. I think this fits well because the typical laissez-faire colony was something that was only indirectly controlled, founded to produce money for the mother country, and produced headaches when they grew too big (in Civ5 terms, puppet cities will eventually be a happiness liability since you need to unpuppet them and build a courthouse).
Proposal: At some point in the Renaissance (probably Navigation), allow the building of a new unit: The Colonist. The Colonist can build Colonies, which are self-created puppet cities. In addition, the Conquistador should found colonies as well. For game purposes, they will act like regular puppet cities both in happiness costs and in that they don't add to social policy costs. One strategy this opens is the option to get a second wave of expansion and a chance to give larger empires a cultural victory without requiring them to conquer. On the other hand, the delayed expansion (Renaissance) will help mitigate this strategy too much.
Advanced Proposal: I don't think it's necessary, but an argument could be made to give the option to give puppet cities independence. The simplest way I can think of is a menu option where you can select which puppet cities will belong to the newly freed colony.
Vassals
I wrote too much about colonies, so I'll try to make this one shorter. Basically, this one will take advantage of one of the most prominent Civ5 features - City-States. Everything I say will be tentative since I don't know how they're changing the ability to be friends with them. Essentially, when you conquer a City-State, you would not be required to take control of it. You would also get the option to force the CS to capitulate and become your vassal. Essentially, the CS would become "allied" but you would be penalized because that friendship would degrade at a much faster rate. I think this feature would go well with new things like covert espionage missions only without any of the subtlety. I would assume there would be diplomatic penalties, certainly with anyone that was currently allied with the CS.
I feel this will otherwise mirror Civ4 vassals well. CS are dependent on your diplomacy, they come to your aid if you are at war, and they'll give you benefits and access to resources.
So those are my proposals. I feel this adds strategic diversity without simply copy and pasting Civ4 features. Similar to how they're bringing back religion without making it the old version of religion.
Colonies
Colonies are pretty straight forward to implement. The biggest thing about a colony in Civ4 was that you did not directly control them, but they contributed towards your civilization. In Civ4, they were essentially self-created vassal states. However, in Civ5, the most obvious analogy are Puppet Cities. I think this fits well because the typical laissez-faire colony was something that was only indirectly controlled, founded to produce money for the mother country, and produced headaches when they grew too big (in Civ5 terms, puppet cities will eventually be a happiness liability since you need to unpuppet them and build a courthouse).
Proposal: At some point in the Renaissance (probably Navigation), allow the building of a new unit: The Colonist. The Colonist can build Colonies, which are self-created puppet cities. In addition, the Conquistador should found colonies as well. For game purposes, they will act like regular puppet cities both in happiness costs and in that they don't add to social policy costs. One strategy this opens is the option to get a second wave of expansion and a chance to give larger empires a cultural victory without requiring them to conquer. On the other hand, the delayed expansion (Renaissance) will help mitigate this strategy too much.
Advanced Proposal: I don't think it's necessary, but an argument could be made to give the option to give puppet cities independence. The simplest way I can think of is a menu option where you can select which puppet cities will belong to the newly freed colony.
Vassals
I wrote too much about colonies, so I'll try to make this one shorter. Basically, this one will take advantage of one of the most prominent Civ5 features - City-States. Everything I say will be tentative since I don't know how they're changing the ability to be friends with them. Essentially, when you conquer a City-State, you would not be required to take control of it. You would also get the option to force the CS to capitulate and become your vassal. Essentially, the CS would become "allied" but you would be penalized because that friendship would degrade at a much faster rate. I think this feature would go well with new things like covert espionage missions only without any of the subtlety. I would assume there would be diplomatic penalties, certainly with anyone that was currently allied with the CS.
I feel this will otherwise mirror Civ4 vassals well. CS are dependent on your diplomacy, they come to your aid if you are at war, and they'll give you benefits and access to resources.
So those are my proposals. I feel this adds strategic diversity without simply copy and pasting Civ4 features. Similar to how they're bringing back religion without making it the old version of religion.