Why should I be pressured into getting onto a higher level? Why should I be like everybody else and beat the game on Diety sweating over ebing scared of making a single bad move causing me to completely lose? Warlord is fine as it is, it's easy enough for me to know I can casually relax and expand, without being worried about the AI owning me, but at the same time ocassionaly being attacked only to repel.
I like the Civ the way it is, and quite frankly don't even find the diplomacy broken in most cases. Besides, Civ 5 came out in '10, not '06.