I agree the fairs could have more going on, and I LOVE the ideas about commemorative collectible teacups and the like. I also think a usable tea set would have been perfect for this pack, and this has long been something I have wanted in the game. They also could have included it with snowy escape. Japanese tea ceremony? That was a missed opportunity.
Still, I like that my sims can get an increase in profit on their sales at the stalls, and I use the fairs as opportunities to get errands and work on completing them. Some speculation about the fairs. Don't know if these are legit or not.
1. I don't think one Sim can win two categories at the same fair, and submitting more than one entry seems to diminish your chance of winning. If you have a rainbow cow who's very happy, and excellent strawberry milk, submit the cow because it is more rare and more likely to win its category.
2. Socializing with your animal entries once submitted seems to help their chances, so don't submit your rainbow cow and then just leave it. Come back and give it attention every now and then.
Those are just some theories I have! Maybe they will help.