As in all GC games, Tourism still remains significantly overpowered. It is basically free money, depending on the number of planets you have, without building anything. No effort at all. So civs with just a few colonies will suck here. Now that there are Tourism boosting improvements in the main categories, their role became very minor and less significant.
Having a lot of GC experience now, I strongly think that Tourism and Wealth should take a different path, as they are actually both income money, but Tourism is just cheap. So instead of only one or two Tourism buildings total, they could be like shopping malls, so you can fill a planet with them if you want. You could decide between a market based economy or tourists based economy on a given planet (so having Tourism as a separate type now makes sense, and also worth to utilize adjacency bonuses).
The kick here would be that let the Wealth be only dependent on Population factors, and Tourism be only affected by a planet's Influence (and/or other factors like planet quality etc.). Therefore there would be planets that are boring and rarely visited by tourists (not beneficial to improve on their Tourism factors) and other planets would be tourist paradises (that worth to be filled with tourist attraction buildings). So now you could choose between two types of money gain, resulting in more customized planets. This concept would only work with a non-linear increase of Tourism, as Influence differs less. So less influenced planets should have almost useless tourisms, while considerable influence means higher tourism, and Influence capitals would bring extreme tourism rates.
This way you could balance the income of Tourism, even if you have less number of planets with higher influences in exchange. This would reduce the "free money" effect more, if done right - or at least balance this between civilizations.