Perhaps I am near sighted - or simply optimistic - but I honestly think that there is less emphasis on the military aspect of the game. By that I mean that the military aspect of the game has been made less powerful and less of a crutch. I do think that the military aspect of the game has been made more interesting, though.
Maybe it's a function of the level I play (Monarch, usually), but in Civ IV, you could use a strong military to leverage your way to any of the available victory conditions, because more cities meant more of everything else - more gold, more science, more production, more units, more votes in the UN. . . It was the classic snowball effect, and - because of the limitless stack mechanism - it was unstoppable: whether you were on offense or defense, the size of your stack was the biggest factor in any war.
The 1upH mechanic means that war will be more interesting - we will have to pay more attention to it - but it also means that other factors become much more relevant in determining who will win, such as: the size of the front, the terrain, how your units are deployed. . . and a host of other factors.
But, in the grander scope of the game, war has become less powerful. It cannot be leveraged into a diplomatic victory - and may actually make that victory condition unattainable. Global happiness means that there is a limit to how much you can benefit from conquered cities. Puppets allow some wiggle room, but do not add units or production capability to your empire.
More cities means that Social policies cost more, so that smaller empires might be better positioned to achieve a Culture Victory - and continuous conquest will increase those costs without really giving you the means to make up the difference - probably putting that VC out of reach as well.
Research pacts require long term friends, which will be harder to find for aggressive, warmongering civs, meaning that they may tech slower, making a Scientific Victory harder to achieve.
Continuous aggression may very well limit you to a Domination Victory. If that proves to be the case, then the military aspect of the game is less powerful.
Since conquered cities bring their acquired tiles with them - there is even a place for limited conquest (which became more and more difficult in Civ IV, the later in the game you went, because of overwhelming native culture).
