Quoting myself from teh discord:
So on Progress, I am a big progress player, Peaceful wide is my favorite style, so I have a lot of experience with it. I've also done side by side comparisons of Tradition and Progress using the same start to get a deeper understanding. I think people underestimate the general bonuses of Progress. Progress has a few key strengths: 1) It has a very solid early game science. I always tech faster as progress than tradition for all of the early game into mid game. 2) Once you get the closer Progress does generate a good bit more gold than the other trees. 3) Progress' cities become "operational" faster than either other tree. You get a solid hammer and food base combined with the extra gold for more infrastructure buys. While its true Tradition can expand quicker than progress initially, Progress very quickly matches and then exceeds, because Progress' secondary cities very quickly become capable of good settler production as well. So with Tradition I often have to balance my capital with settler production, with progress its quite simple to shift that burden to satellites and let my capital start to grow back up. So all of that to say is.... Progress' early game is just fine. You expand fast, your cities develop quicker, and you get a tech head start.(edited)
[10:05 PM]
If Progress has any issues, its more in the mid game. Happiness I think is a problem for Progress still, that food is great when your city is getting started, and useful when your cranking out settlers. But after that phase its hard to grow up your cities without happiness issues. Science Wise, CrazyG did a good breakdown of how Tradition starts to overtake Progress in terms of science yields later in the game, and I agree. So while I tech faster as progress initially, you start to lose that lead and eventually I think Tradition does tech quicker. So my recommendation: Any change to progress should be considered with its Closer. The tree itself doesn't need anything, I really think its fine. If you really want to change something in Progress, you could add something to the closer so it doesn't pop up too early in the game, but does help the tree continue to push later in the game. As for the TR idea, I generally liked the concept, especially since Progress is often a natural fit for the "TR focused" civs like Portugal, Morocco, etc.