AI in solitaire/co-op boardgames: How should it work?

That’s a good example, but I think you’re right that it’s more of a puzzle where taking into account possible AI behaviors is part of the puzzle. It’s worth noting the core concept is that players can “use” the AI against each other, as you point out. And I don’t think it carries over into solitaire very smoothly. I’d argue that Andrew Park’s attempt at a dungeon crawl does some clever stuff, but the solitaire mode isn’t very well thought out on a number of fronts, and the AI is one of those fronts.

Right, and that’s part of what I’m talking about. That shouldn’t happen. The system shouldn’t require me to play on its behalf.

As for your examples, I think they speak just fine for how it’s a problematic issue. I don’t know Marvel United – it’s the same fella who did Dungeon Alliance, by the way – but Gloomhaven is a great example of a game that can’t follow through with what it’s attempting. Both of your examples are the designer saying, “Look, I took the decision tree as far as I can, so if it has to go any further, eh, I guess just take over for me.” That’s your idea of a “totally valid design approach”? Wouldn’t it be a better design if the game and an AI decision tree that fit each other? In other words, wouldn’t a better design be one that doesn’t fall apart and ask me to step in an adjudicate?

-Tom