I'm not sure any of you had time to read my massive Innovation essay earlier, but since I love you all so much I played 3 more games of it against myself tonight. Well that, and I was determined to play at least one more game with an expansion before putting the box under my Table Of Shame where games I basically never play go. Thankfully there aren't a massive number of games there.
All 3 games were 2-player against myself. The first 2 I realized several turns in that I had forgotten to use any of the expansion triggers, so I played them out as normal games. The third game I finally remembered and played with the Cities expansion for a second time. Hopefully I remembered all the occasions I was supposed to draw a city. Unfortunately, the first 2 games I might have forgotten to only take 1 action for the first player. The third game I hope I remembered but I'm not 100% sure. Ideally this wouldn't make a huge difference and I don't think the same player won every time.
At any rate, I did the games partly as an experiment to see if I was completely crazy about the achievement thing in 2-player games. I decided my lefthand player would always try to win by score + achievements, and my righthand player would try to get to a 9+ card and possibly win that way, attacking and blocking the lefthand player if needed, e.g. by grabbing achievements early if necessary.
The results were overwhelming. Game 1, someone won 6 achievements to 0. I think it was the player who was trying to do it. Game 2, someone won 6 achievements to 1 I think? Game 3, it was either 2-7 or 3-7, and the winning player didn't even want the achievements per se. In none of the 3 games did a single 8 or higher card get drawn. In fact, only one 7 value card got used in the first game, and only to score and win the game! The other games used some 7-value cards.
For the Cities game, I used the Endorse action maybe 3-4 times. It does seem powerful in some cases, since you can use a dogma 3 times on your turn, or 2 times and grab an achievement. However, out of 105 base cards and 105 cities cards, I think 70 of the base cards got used but only maybe 12 of the cities cards. The sheer amount of cities cards feels a bit silly and redundant because of this, since if you get one that's actually useful to you it's presumably sheer luck. (This is assuming my understanding of the rules is correct, namely that you cannot draw another city card once you have one in your hand.)
My conclusion: If you play 2-player Innovation with the rules as written, someone is very likely to win by achievements without the lategame cards even being used.