It would be if they were trying to make the AIs "beat the player" and nothing else, but that's not what they're doing. They're trying to make the AI less predictable, less like a math equation, and more "realistic" in their actions. The idea is it doesn't matter how much you've buttered up a civ if they see you as being too good of a treat to pass up (obviously depending on AI, I doubt Ghandi will be doing this much). And also, having a game where the AIs can win, instead of Civ 4, where the AI can make the player lose.
It's far more like how real nations act: Long term relationships do make people more friendly, but hostile actions (like mobilizing troops on their border, or blocking their expansion), will not be ignored. Leaders will vary in how they behave like Civ 4, but unlike civ 4 you cannot absolutely predict their actions since the modifier system is gone, and the AIs have shifts in their flavors between games. If you refuse to help a civ when it is being attacked, then they aren't going to treat you as a friend any more (Although I expect that you could repair relations given time).
Is it more difficult? Yes. Will the AI gang up on humans? No.
Will the AI act according to the reality of the situation combined with their personality? That's the idea at least.