Well here goes. Governor Review (assuming they don't alter the current bonuses). Just commenting on their specific abilities below but of course all of them give 8 loyalty pressure which could be really great or not depending on how loyalty plays out.
Magnus: Assuming they don't alter chopping he is just totally overpowered. He is the first governor to hire - and with 1 promotion you can chop spam out settlers all day long. 100% chop bonus plus 80% settler production with Colonization and no loss of population!!

A second promotion allows you to ignore strategic resources. I doubt I'd ever bother with his other promotions however.
Total titles needed (3) (1 to hire and 2 for promotions)
Liang: Builder charges, yes please. And another two promotions on the left side for bonuses to city center and district production. The two improvements (aquaculture and parks) both look pretty weak but in a culture game you might want the parks.
Total titles needed (3)
Pingala: Good solid bonuses for either culture and/or science. But he is a later governor to hire. Clearly if you are going for a science victory you will max out his tree. Nukes I never build so that is the only promotion I wouldn't ever use.
Total titles needed - Science game (4), Culture game (2)
Amani - I'm kind of confused about her abilities. Affluence - city-state provided a copy of its luxury resources. Don't they already do this if you are suzi? And if you are committing Amani to a CS you would expect to become suzi. Emissary/Prestige are offensive/defensive loyalty bonuses - need to see the details of loyalty to see how useful this is. Promoter is a great amenity boost. While Puppeteer is fantastic for controlling a CS although I don't generally have trouble finding enough envoys to control the city states I really want anyway.
Reyna: Seems pretty weak actually - quicker tile acquisition seems very poor compared to the others base abilities. I guess it depends on how fast it is. She would be very nice if you have one large coastal city but otherwise? Buying districts with gold seems good but it takes three promotions and we don't know how much they will cost. It may just continue to be easier to chop them in (see Magnus above).
Moksha - Well if you aren't bothering about religion then you can skip him. His bonuses are kind of strange actually. Three of his 5 promotions are defensive. I don't think I've ever had any difficulty defending my religion for the AI so these seem useless. His base religious pressure is kind of weak also. Pressure isn't that strong in Civ 6 although he could work well in your holy city I guess. The production bonus is solid and Patron Saint is great.
Total titles needed - Religion Conquest game (4)
Victor - Basically useless for the human player as he is all defensive. - might be helpful for the AI. If warmongering his 3 turn deployment might be good if you need to quick forward settle him in captured cities for the loyalty bonus.
Do we have any idea how many governor titles we get in the game. There are 4 for the government district and its three buildings. One wonder. And I think I've seen 10+ on the civics tree. I can't see really needing more than a dozen to get most of the important stuff for whatever victory condition you are shooting for. A few more if you want all 7 for the loyalty bonuses.
I expect they may still tweak their bonuses before release but regardless it will be fun playing around with them.