That whole story arc of hers is still so silly and ridiculous to me that it kind of brings down the otherwise great quality of the game. (Only a little bit, though.)
I know it will never change now, but it could have worked better without knocking down her house to build a barn if the Daisy storyline was incorporated into her storyline. It could have been that, after the MC sees Diane is really tired from all the milking, he finds the first piece of her statuette when doing the gardening and then once he brings her to life, Diane discovers that Daisy can produce lots of milk easily and regularly because she's half-cow. This way she wouldn't have had to knock down the house to build the barn and instead could milk Daisy in the shed and keep her business going.