I think part of the problem here is how we are calculating the benefit of GP. The raw number of GP is important, but what is more important is the number of turns we can utilize the GP benefit. Earlier GP are more valuable then later GP. So I wrote a very simple program that will calculate the number of GP and the number of turns you can utilize a GP based on the number of cities and the GPP/turn for each city. For the sake of the argument lets assume each GP generated is a Great Scientist and he is settled right away. The results were very interesting. Here are a few comparisons:
Early Game, assuming you are running two specialists in each city over the course of 100 Turns and you have not generated a single GP yet:
Edit: Sorry about the formatting, I am not sure why the columns are not aligned!
Code:
GP GP Turn Benefit
PHILO Civ
1 City: 4 232 Turns
2 Cities 6 315 Turns
3 Cities 7 373 Turns
4 Cities 8 414 Turns
10 Cities 10 538 Turns
Non Philo Civ
1 City 3 133 Turns
2 Cities 4 182 Turns
3 Cities 4 215 Turns
4 Cities 5 232 Turns
10 Cities 6 248 Turns
In the early game the PH civ is getting a very big boost in the GP Turns! Comparing 4 cities running 2 scientists in each the PH civ will generate three extra GP and an extra 1,092 est beakers. That is an easy medieval tech or two. The gap grows even bigger if you are running Rep. Much more powerful then I originally thought.
Mid Game, (We will use the questions from Voice of Unreason. 1 City running 8 specialists, and all other cities running 6 specialists). But you have already created 5 Specialists.
Code:
GP GP Turn Benefit
Philo Civ
1 Main City 5 268 Turns
1 Main City, 1 Other City 7 383 Turns
1 Main City, 2 Other Cities 9 457 Turns
1 Main City, 3 Other Cities 9 528 Turns
1 Main City, 9 Other Cities 13 723 Turns
Non Philo Civ
1 Main City 3 132 Turns
1 Main City, 1 Other City 5 188 Turns
1 Main City, 2 Other Cities 5 233 Turns
1 Main City, 3 Other Cities 5 274 Turns
1 Main City, 9 Other Cities 9 351 Turns
Again the PH civ is beating out the non-ph civ quite nicely. And keep in mind that this comparison is not really realistic. The PH civ will probably already have a couple of extra settled GP over the non ph civ. The total GP produced does not include the five you already started with.
Now lets see what happens if the PH civ is running Pacifism
Code:
GP GP Turn Benefit
1 Main City 7 379 Turns
1 Main City, 1 Other City 10 526 Turns
1 Main City, 2 Other Cities 11 637 Turns
1 Main City, 3 Other Cities 13 717 Turns
1 Main City, 9 Other Cities 18 1,002 Turns
That is a very nice boost and proves in my mind that a PH civ can gain quite a bit in the mid game by running Pacifism.
So to summarize all that data and a couple of key points:
1. PHILO gives a solid turn advantage in creating GP which can easily translate into a extra tech, a ton of gold or extra hammers. Far stronger then Org in the early and mid game.
2. A PHILO civ should run specialists in multiple cities. Probably around three. After that point you get diminishing returns.
3. A PHILO civ should consider switching to pacifism once that civic becomes available.
4. GP have a bigger impact in the early game then in the late game
5. Early GP are dirt cheap and a great bargain especially the first 10. From 10 to 15 they start to get much more expensive. After 15 they are extremely expense.
6. Philo can generate extra GPP with very little investment - both in the number of specialists needed, hammers invested (National Epic and Parthenon) or civics (Pacifism).
7. The opportunity cost is to run specialists in the early game is much lower. After liberalism the opportunity cost to run specialists is much higher (Due to Free Speech & Printing Press). You will reach a point where it does not make sense to keep chasing GP.