I missed the feedback form, but as a general rule I don't think lone city wonders tend to be all that appealing unless they're very strong. I mean nobody cares about the Temple of Artemis but Great Library is generally considered a solid wonder.
I'm not sure what the ideal power level for a wonder should be, really. I think they should be closer to "things you can base a gameplan around" rather than "nice little bonus" or "OMG must have." Spending too much time on that of course is how you end up with some other balance mods, where you just end up changing the whole game. Maybe make it 2 free merchants, no tile yield bonus? Of course, Great Library has a hidden cost of researching a path you generally only take for wonders while Colossus is gained at a tech everyone must research because of the key building it holds. Just spitballing.
I'm not sure what the ideal power level for a wonder should be, really. I think they should be closer to "things you can base a gameplan around" rather than "nice little bonus" or "OMG must have." Spending too much time on that of course is how you end up with some other balance mods, where you just end up changing the whole game. Maybe make it 2 free merchants, no tile yield bonus? Of course, Great Library has a hidden cost of researching a path you generally only take for wonders while Colossus is gained at a tech everyone must research because of the key building it holds. Just spitballing.
I've got some dirt on my shoulder, can you brush it off for me?