Well said! 

If you look at it the other way, I think it would be very frustrating if you had the upper hand and wanted to finish off an opponent and the game would constantly help him in some way to stay in the game...

Really I think it depends what you mean by underdog. Frogboy made a great post about victory conditions a while back (sigh, I can't find it...). But to summarize, one player might have a unstoppable military, and it looks like it's only a matter of time before the entire world succumbs to it. But another player might be well on his way to casting a major world-wrecking spell that will completely change the game - the player with the unstoppable military might topple over, indeed most empires would probably suffer huge damage, leaving the caster of the spell in a very good place. And yet another player might be well on his way to completing his Master Quest, snatching victory from both the military superpower and the magical destroyer. And who knows what other victory conditions might be available.

I think that's the best way to handle the 'underdog' problem. Make it very difficult to tell who is actually an underdog; if a powerful empire sends a huge force to roll over a smaller, seemingly innocuous nation, maybe just before the killing blow is struck to the smaller nation's capital city, the defending channeler will utterly destroy the invading army with the culmination of a powerful spell that has been a long time in the making. But at the same time, if you (or any other player, human or AI) are on the losing side of a struggle and have no tricks up your sleeves, the game should definitely not come and save you. Basically - if you are straight up inferior to another nation, it should be quite a challenge to defeat said nation.

Basically, I think that providing many options with which to handle a situation is the best way to make underdog scenarios less clear. You shouldn't necessarily be doomed just because the nearest military superpower has declared war on you - you may not being able to match it militarily, but maybe your magic or allies or something else you've been preparing can save you; and these means that you never were really the underdog - it just means that instead of focusing on military might you focused on different, but equally important, aspects of your empire.

That's me! I often turn off all but one or two military conditions, but because of me not other players. Sometimes I'm just really in the mood to take over the world, but somehow it almost always turns out to be a lot easier for me to win through an alliance, tech or culture victory. In fact I often find that on my way to a conquest victory I accidentally win by another means, or have to actively stimmy some aspect of my empire to prevent a premature victory through a means I don't want. Although at the same time the other methods of victory can be convenient ways to get your victory without having to do all the boring mop up at the end of world-wide (or galaxy-wide) conquest...

Hopefully Stardock figures out the right balance so that it's rather difficult to... stumble into another type of victory while actively striving for a conquest victory.

I think that MoM went in the right direction with the distance cost multiplier when you Wizard cast spells in combat.  If you expand this into a CIV like corruption effect you can make large empires less efficent.  It has been shown that this is not enough to change the course of a game that has too large of a ballance of power difference but it allows for a small efficent empire to be more then a speed bump.

Sammual

I agree, it needs to scale with map size.

Sammual

I advise not changing the course of a games history in your favor because that's a huge unfair advantage.  I won't go into detail and this topic has been previously discussed within another thread so let's not throw this topic off course with responses.

I just wanted to comment on a personal experience where I had the option to quit a game I was losing, yet I chose to keep playing.  It was in Dominions_3 where a new enemy appeared on my borders and was much stronger.  I quickly organized my best armies and supercombatants to face him.  Since my opponent was an AI I felt I had the advantage yet soon learned his greater numbers crushed my strategic battlefield orders and placement of units.  My best armies fell one by one and each turn I was losing more and more land to him.  Every battle he seemed to have larger and larger armies with more mages.  He pushed me all the way back to my capital and my strongest army which was wounded had no choice but to guard the neighboring province below my capital in an effort to protect my remaining provinces providing my last sources of income and gems(my belly).  I felt certain he would march onto my capital and begin laying siege...  I lost so much that winning the game seemed utterly hopeless, but I kept playing.    Surprisingly one turn passed where he didn't attack my capital or my army to the south... it was a breath of fresh air to strengthen my defensives.  Then the second turn passed and he once again did not attack, but his forces were still too large for me to do anything except hold my ground.  Then a few more turns passed and his armies on the border began shrinking... I had no idea why, but every turn I was healing and strengthening.  Then eventually the truth behind the mystery appeared a much more powerful empire was actually swallowing him and took over the territories he stole from me.  I felt like a coyote watching a T-Rex chow down on a lion which had me pinned.  Surprisingly the stronger empire(T-Rex) did not attack me which allowed me to attack and expand into other areas of the map and eventually, much later, take down the mighty T-Rex which unknowningly saved me earlier in the game.    

I would have missed that incredible set of events and my mighty comeback if I would have quit that game or used some type of reload (via 3rd party tool).

I like these ideas. I would actually like to be able to disable the graphs for singleplayer, too. The AI solutions are great too; although instead of having totally separate AIs behaving drastically differently (some ganging up on the most powerful opponents, some picking on weaker ones, etc), I would prefer an adaptable AI that can make the decision, "will I be better off by conquering that weakling to my east, or by joining the alliance forming to put a stop to Blue Player's unchecked expansion and unmatched might?" It would make games more unpredictable in a very good way, although I imagine it'd be real hard to code.