I am talking about Civ6 too. I was merely giving an example that Maximising Follower Beliefs won't be passive or restrictive, based on my Civ5 game, Does religion spread look massively different? My example indicated that there is a lot of strategic Choice in India's abilities.
According to Arioch so far their is only one followers belief tied to number of Followers however the numbers of follower beliefs do look limited. To really maximise the gameplay of India's ability i would give the player reasons to balance the religions one way or the other, in one city or another. Consider Work Ethic, You would want the dominant religion to be the one with work ethic as its bonus is linked to number of followers. If perhaps there are more Follower beliefs, you could theoretically choose between 2 different religions that you are actively spreading to different cities, based on the city specialisation, in order to make the most of the beliefs. That sounds like nuanced strategic choice to me.
Kongo is actually quite Active. Yes you cant choose which religions get spread to you but certainly can choose what religion stays. ---
Part of Kongo i feel is timing your strategies based on the order that religions are spread to you. You First get Religion A which helps with growth, so you build around that. You then get Religion B which helps with Culture, so you initate the purges and build around Religion B Etc. Timing when to switch Founders Beliefs i feel is going to be important to a Kongo playthrough and is flexible as well as active, it is just you cant actually pick them yourself.
The Power Part of Kongo obviously stems from its special ability, Minkisi which is all about Great Works. How you get those great works is up to you. Are you going to Find them, Steal them, Loot them, Create Them. The bonus is passive but how you acquire the bonus is entirely up to you/. That is quite flexible in my mind. I think Kongo is quite flexible, from a different point of view.