So, we played our first two games tonight and they were a blast. We only had 3 players, so I'm sure that colored our experience a bit, but the color that most comes to mind is a sickly shade of green: Nurgle won both games in pretty crushing fashion with victory points totals over 50.
The first game saw Tzeentch and Slaanesh pitted against Nurgle and was the closer of the two. Tzeentch lagged behind while he figured out how to maximize his effectiveness between magic symbols and warpstone tokens, but there were only 3 that ever appeared on the board and one of those was from a dial upgrade. Slaanesh did well enough corrupting Nobles but as soon as Nurgle achieved the Great Unclean One upgrade, meaning that he could spend 3 power points per turn and automatically get a dial tick no matter what the other players did, he started moving ahead. More corruption meant a snowball of ruination in the next couple turns which he further capitalized upon with Provender of Ruin, so that even when Slaanesh won first place on a couple Ruin cards and hit 54 points, Nurgle was still 19 points ahead of that total.
The second game saw Slaanesh replaced with Khorne and we found that the Blood God was an excellent answer for Nurgle, simply by chasing his cultists everywhere with Bloodletters. However, the second Old World card that emerged was Electors Sue for Peace. As Nurgle had the lowest Threat at the time, he placed both Event tokens in Brettonia and The Empire, two populous regions in the center of the board. That card stayed in place for the rest of the game, so that his cultists could never be removed from those two regions, which meant he was constantly getting dial ticks and, of course, the first chance he took to get an upgrade brought out the Great Unclean One again. 3 points per turn sending the GUO to Kislev and Estalia meant 1 or 2 ticks per turn, as well as consistent plays of Plague Aura, giving him domination of The Empire and Brettonia every turn which neither of the other gods could do anything about (Khorne doesn't have enough cultists to ruin either and combat couldn't take place there; there was no Warpstone in either region so Tzeentch was hampered) and another runaway VP win.
I guess my question would be: why would you ever play any upgrade card before GUO? Nurgle's dial track may be the longest, but every step adds another bonus and if you can do it for an expenditure of points which is easily met, why wouldn't you? That expenditure of points also brings a combat monster and the use of that GUO also brings access to the other, lesser upgrade cards for virtually nothing. One of the things I really enjoy about the game is the variety of tough decisions that need to be made by each player in terms of playing cards and placing figures, but the use of the first upgrade for Nurgle is a virtual no-brainer. It opens up everything else that Nurgle can do and is relatively impossible for the other players to affect.
We're definitely going to try to get some 4-player games in to see if it changes the experience at all. Overall, it's an excellent game, but that one path to victory just strikes me as a bit too obvious.