The main reason I see that people want others to build on a baseplate is that it becomes easier to clear if it is spam. For instance, would you like to dwand every brick on the ground in a house made of 1x1s? If its on a baseplate, one hit and it's all gone. Also, building on a baseplate doesn't restrict circular buildings. If anything, it can make them better. Think about it. Would you like a house with no floor? Besides, builds can look perfectly fine with a baseplate, even if they arn't square. Just add a couple things on the plate to make it look like a lawn for instance. Or make it like a parking lot. There's tons of ways to make it look just fine.