I've noticed, too, that Commercial/Agricultural (Iroquois) has nice synergy -- with extra food and cheap aqueducts, the commerce bonus stops being so "theoretical." I'm playing a huge-map game right now and will reach 0 AD with about 10 cities receiving the bonus. (Due in part, however, to a vast number of rivers and a successful Philosophy gambit... more on that below.) Only problem I've seen is that to really apply that commerce, you have to build infrastructure, which means that it's hard to get your military rolling in time to still send out your Mounted Warriors against spearmen, rather than pikemen. (Of course, if I'd been more careful about whoring governmental techs, my neighbors wouldn't be cranking out the beakers so fast...)
The new Philosophy behavior REALLY helps out seafaring and commercial civs, because any combination, even a fairly ho-hum one, of a) luck, b) skill, and c) a sufficiently low level (I've done it thrice on Emperor!) will let you pull off a Code of Laws --> Philosophy --> Republic gambit. Sure, you end up entering Republic under poor conditions for a Republic (small number of small towns)... but not if you play with an early switch in mind from the start. And it's STILL better than despotism.