It's not independent. It's easier for a big civ to spare cash needed to buy CSs. In Civ4, it was perfectly possible to win diplo with one city civ, so there isn't any kind of improvement in that regard.
In any Civ game, everything ultimately comes down to population. The importance of the 1 vote per civ condition is that you can't win by pseudo-domination, at least not as easily - certainly you can if you wipe out practically every other Civ, but the easy route to diplo victory in every other Civ game is to spam the map and take out/capture just enough opposing cities to claim a majority.
I don't think they will ever remove this. It would be against their leading design principle that the AI should play for win.
If only it was a leading design principle that the AI should play to win. Instead it seems to be a leading design principle that the AI should play to beat the human, regardless of how that affects its standing or chances of victory vs. other AIs, or any calculation as to how it would remain competitive if its attack fails. AIs would make more intelligent decisions and there would be more competition over e.g. city-states if they actually played to win. And it's perfectly possible for a civ to play to win without voting for itself (in fact, if the leading civ has 6 votes through city-states, it's in a 'minor' civ's best interests to vote for whichever other civ has the most votes to force a stalemate and delay a diplomatic victory - which is how the AI played in older Civ games). Which two civs get the chance of being elected can still be determined by population or map presence, they just would only get one vote each and the minor civs, and city-states, would have to choose which of them to vote for.
The worst part of CIV5 is dealing with the many problems with Steam. I was having so many issues with Steam crashes that I finally uninstalled the game and sent a letter to 2K letting them know I wasn't happy with having to deal with Steam in order to play the game. This game should have been complete in the box and not rely on a 3rd party that doesn't have it's act together. Steam stinks.
I'm sorry to derail the topic here, but Steam is not a problem. In fact it has saved PC gaming IMO. I mean, Portal 2 for 7 bucks? SEVEN DOLLARS!?! ALL HAIL STEAM!
Except for the fact that it comes with irritating pop-ups and seems to be responsible for delayed loading in games (most Steam games I have load slowly - esp Civ V and Shogun 2), I have no problem with Steam (although it has prompted me to spend lots of money on games on offer that I hardly, and in some cases, haven't played - admottedly some, like Sins of a Solar Empire, are games I was interested in anyway that just turned out not to be very good, but I've got all sorts of random clutter as well). Unlike many, I actually like the DLC model in principle even if the prices and content often leave a lot to be desired, and Civ V actually has some of the better DLC content I've seen - look at what other games offer. I mean come on, cosmetic graphics packs? Would anyone pay for those, and if so why? Aside from the Rise of the Samurai campaign, the best the Total War series offers - aside from yet more random cosmetic upgrades like 'blood packs' - are extra unnecessary units, half of which seem to have been designed just for the sake of adding variety rather than with any regard to the historical setting. Bulletproof Monks that actually resist firearms? Warrior nuns?
I do however disagree with game designers imposing Steam on people rather than having it as an option, especially for games that are predominantly single-player like the Civ series.