Firstly: I know many people believe king tributes are already excessive, this suggestion has nothing to do with that, that is a separate topic.
Suggestion: Increase the amount of resources generated by "NPC Vassal" for kings during the first few days.
Why: Spawning as a governor has a huge advantage in early game progression over a King, this will even the playing field a bit whilst also encouraging more players to play as a king and hopefully remain that way. This could lead to more exciting early and mid-game sparing with the increased amount of kingdoms.
Furthermore: The current meta includes spawning in as a governor, and utilizing the Robber Hideout mechanics and Quest Rewards to gain the most resources and quickly establish a second village on a "cropper". Once you've settled, then the players who want to be king will switch. I've tried spawning in as a king, filling every spot I have available with a governor; but it's not even close to being as fast as a speed settler. Currently if you intend to play as a king, it is still better to spawn as a governor and then switch later. This is just illogical.
In the attached images you will notice how, even though I have all my available spots filled with high-prestiged and eager-to-be-Menhir'd governors (the majority of players), they have little-to-none tribute production for me as a king and clearly they are all planning to speed settle. I stand no chance against my neighbors in the upcoming days if I intend to continue playing as a king here. So I will be forced to abdicate and join some other kingdom who likely started as governors.
I believe there was a recent update in which the mentioned intention was to help increase the amount of kingdoms. If that is something Travian believes to be beneficial to the early/mid game action then adopting this idea would push that motive even further.
I hope I have explained myself well, let me know if you have any questions.