I finally tried Phoenicia and had a very nice scientific victory (first one on GS, and I must say it's still tedious...).
I played on an "island plates" map of course, and was very lucky to meet Mohenjo Daro, which helped immensely : I did not have to settle near fresh water, only look for the best cothon+CS spots, and my cities grew fast which allowed for a ton of districts.
Ok I was quite impressed, it was really easy to chop a cothon, buy a lighthouse and a shipyard because of the massive money, buy a CS (Reyna or Moksha take time to settle, just enough to reach 4 pop), buy a settler, rinse and repeat.
Meanwhile, build a massive fleet, with the bireme which can face barbarian quadrirems (finally !), send lucrative sea trade routes and have bireme watch over them.
There are some drawbacks however.
First, building a ton of harbors, before CS, means more admiral than merchant points, and merchants are way more useful, especially when you rely on trade routes.
Without Mohenjo Daro, you won't be so free to choose great cothon spots and/or you won't have a very high pop, which means you won't build so many districts, and you need more more more because of the cothon.
And on big landmasses, well it's not so fun.
And that whole ICS on island maps is something you can pull with another civ.
But it won't be so easy. You'll have less money. And you will face loyalty issues. And you won't have the "move capital remotely then build casa and enjoy" trick.
Ok I see the point and the synergy now