About the DoWs people are getting:
I'm playing for the most part with an "Always War" attitude on Emperor through Diety. If I catch an AI unit on open terrain with my initial warrior, I attack. If I can do significant damage and stay safe on a hill/forest, I attack. If an AI unit has just fought a Barb, I attack. Very early in the game, there is nothing to lose (except for the long-term diplo effects). You have no tiles to be pillaged, no workers to protect, and your capital can take care of its own defense against the starting AI units.
The earlier the wars start, the less time the AI has to peacefully assemble the critical mass of units that can actually hurt me. My cities are picking off his early units one by one, because exploring the other side of my territory seems to be a HUGE priority for the AI early on. On Diety, this is also one of few times I have anything remotely resembling tech parity with the AI. (I haven't tried the REX-ICS techmonster on Diety yet...still working out the kinks on Emperor)
The upside of this is that I almost never get DoW'd by an AI I'm not prepared for. I don't have to build as much military to stay even in their eyes because they've been losing units over time.
The downside is obviously the diplo hit, but I haven't seen a huge effect from that. The AI seems to respect relative army strength much more than diplo history.
I think a key part of this is hunting Scouts asap. If the AI hasn't explored a particular patch of land, it will keep sending single units to it, even if that means running a gauntlet through your ICS crossfire.