imo, the next (balance) patch will weaken french villies and/or lower their gather rates (maybe a few other little things as well, not major), which should weaken france enough. Mercs will be made less all-round-good, but more specific-enemy-good (so they will be great counters for their anti-units, but will be easily killed if not handled well, eg sending black riders vs dragoons). Germany is pretty balanced when mercs are out of the equation, though maybe a vil limit of 80 (rather than 100) would make up for the settler wagon boost (though remember they must "waste" a card on making settler-producing mills).
I haven't played much vs. spain, but I think rushs in general will be made easier to counter (not that rushes will be weaker, but they will be repellable in a more nOOb-friedly way).
It'd be sweet if Ports got age 2 dragoons that did normal (ie not half) damage to villies, giving them a chance to raid effectively. Otto's have an all-round infantry unit; Ports could have an all-round cavalry unit (good against villies, artillery, and cav, but weak vs other dragoons (make them a tad slower plus 1 or 2 less range) and pikes/halbards).
Skirms need to get weakened vs. cavalry, and maybe vs hand-to-hand infantry as well. Maybe just lowering hp would do?
Either way, to actually go back on topic, I reckon the most played civ will become Ports for a bit (people trying out their new strengths), then, if the patch is good, it'll become quite close between all of them. France will lose some popularity, but still stay fairly well-used.
Spain's lancers might go up in price.
And I think that trade posts will cost 300 wood, instead of 250. Ports should get 200 wood (not 250), or 150 wood/50 gold towers.