Parthenon provides you with as much tourism as arena, a normal building that is available earlier. While Parthenon gives you 4 culture and arena only gives you 1, it is easy to get +4 production from arena. At that point arena gives you arguably better yields even though its production cost is just 150, compared to Parthenon's 250 plus scaler. When building an arena, you don't need to worry about someone else getting it first or increasing your future wonder costs. It is true that Parthenon's yield can be improved on early renaissance but it isn't a free buff, since you lose the golden age you could get from the artist. You should also note, that parthenon doesn't give you the base yields of your second great work. You'd get 2 culture and 2 tourism from it anyway if you placed the great work elsewhere. Parthenon lowering boredom is hardly worth mentioning, since you shouldn't be getting any of it anyway, unless you have just founded or conquered the city. It can also be argued that tourism penalties don't really make much difference, since most tourism is gained from historical events, which isn't affected by the tourism modifier.
I can't see how you could find Parthenon better than Hanging gardens or Terracotta army. Hanging gardens (production cost 200 plus scaler) provides you with a free garden (production cost 300), which basically covers the production cost. In addition to that you get 10 food, which allows you either to work your precious specialists even more or focus on tiles that don't provide food. +1 culture isn't much but it's still 25% of Parthenon's culture. Terracotta army's production cost (200 plus scaler) on the other hand is easily covered by the free units you get. For example, skirmisher, catapult and swordsman cost 100 production and horseman costs 90 production. In addition to that you get a golden age, some instant culture (I think 100, not sure) and a unhappiness modifier that can actually gain you a point or two of happiness at some point of the game. There are reasons why you'd want to build Hanging gardens or Terracotta army, while Parthenon is arguably weaker than a normal building that unlocks earlier and costs less.