I ultimately don't mind what my river does, I just want it to ultimately leave an equal amount of space on both sides. Like, I don't want a massive lower section of town and then a wee splinter of land on top because of the river's placement. I wouldn't know what to do with it.
I also like for my town hall and retail to be at the top of the map, close to the train tracks. I have this annoying twinge about running into the back of buildings, so they have to be at the top.
Plaza can go wherever it wants, but it's conveniently at the top with the rest of my things in my town, so that's nifty.
I have a lot of towns and prefer retail and event plaza at the top of map.
One harvest town has the plaza at the bottom and it's a hard to see with all the Perfect trees. Happy artwork is done now.
Town Hall I don't mine where it is. Most towns have the mayors house close to it.
The only thing I prefer is to have not too many lakes lol... I could probably live with everything else. Oh, also not having pears as a native fruit would be nice.
I do quite like having the plaza close to the train station. Otherwise, anything with a good amount of space is good enough for me - the layout I have in mine is irritating in that there are areas that are really narrow, so I can't put any PWP there, and if a villager moves in it's difficult to make the path around their house work.