I always saw Civ as a "build an empire that will last through the centuries" kind of game, not just war. I value diplomacy as well (though I am a little warmonger, I tend to wage wars on AIs that block my expansion). I've read some posts here about the AI being oriented to win and thus making backstabbing and other sneaky tactics the norm, making up ridiculous excuses on the way. I don't like that... I would admire having AIs on somewhat good terms with each other, gang up against a leading civ, but I wouldn't like having to constantly fear that getting ahead would somehow trigger a World War just because the AIs won't come to terms with the fact that they had their chance and they missed it... They ought to assess how far away I am from victory, if I still have some way to go carefully plan alliances that would try to stop me from getting there but still, close friends shouldn't just backstab me like that... Because if they do there is no point really playing nice, I would just try to steamroll everyone from the start and never care for anything other than the domination/conquest victory...
And the devs have gotten it wrong if they think that we players play to win... I just play to enjoy myself, winning is just a bonus, a confirmation that all those plans and schemes and strategies of mine were indeed effective. I enjoy far more a tied game where I have to think my every next move than a game were I press enter just to get it over with.