In the tweaks that I make to the tech tree (small tweaks), I do bring tourism into the game earlier. The Writers guild is moved up to Drama & Poetry so that you can build it earlier. The Artist's Guild is still available at Guilds, but I moved the Museum foward substantially (to Guilds), and also reduced its cost so that the cost of it is the same as an Opera House.
I did that for a couple of reasons. First, is like you mentioned letting tourism play a bigger factor in the game by starting it earlier. Second, I don't like it that you can build an Artist's Guild and generate Great Artists yet have no where to put them besides one slot in the Palace. If you don't have any wonders with Great Artist slot or Cathedrals, then they aren't very useful.
I also made a few other minor changes to the tech tree. One is moving the ability to chop forests over to Mining while changing Mining somewhat. The Heroic Epic is pushed way back until the Medieval era (so that wide empires don't build it). The barracks is moved back one tech to Bronze Working just to make Bronze Working more valuable and also because Barracks are rarely built that early. There just isn't much use in building a Barracks when it only gives 10 experience. 2 battles will give you that. Much smarter to just build the unit and use it right away and gain some experience.
Another change to the tech tree I've been playing with is modifying the early naval techs. Sailing is pushed back from late Ancient era to early Classical era with Calendar as the prereq tech. Sailing gives you Biremes, Triremes, Work Boats, and a new trade route. Optics is pushed back to late Classical era with Sailing as the prereq. Optics gives you the ability to embark, Cargo Ships, Lighthouses, and the Great Lighthouse wonder. I wanted to have Biremes and Triremes unlocked on the same tech while having Cargo Ships a bit later until you've at least had the chance to build some ships with the earlier Sailing tech. I also like the flavor of having units be landlocked during the ancient era. Some may not like that, but I like that style of not being able to do much of anything at the very beginning with new effects gradually being introduced. Navies first appearing in the Classical era is just one of those effects.
The other change has to do with Composite Bowmen. They seem to be the dominant defensive unit for a very long time. Archers disappear almost right after you've built them. Then, you have Composite Bowmen for a long time until Crossbowmen appear later on. So the simple solution is rearranging some of the techs in the classical era. Mathematics is pushed back to the late classical era so it's after Iron Working and Construction. It's just below Engineering in the tech tree. I know it should probably be renamed to something different, but the game play effects work better now.
Another minor change is adding some prerequisite links in the later part of the tree (Modern, Atomic eras) so that you can't beeline only one half of the tree and have Frigates as your ships in the Atomic Era.