I think the game looks cluttered and there are too many buildings. It bothers me to see a building on every tile in the game. I think if someone took the standard farm graphic (which consists of an irrigated field and a barn / building) and removed the buildings from the graphic it would look a lot nicer. I want some tiles that are just nice fields. We have enough buildings in the mines / special resource squares like: pastures, quarries, cottages, lumbermills, workshops, cities once they start expanding, etc etc. We don't need a building graphic on a farm tile too.
Btw, I think the reason they don't take up the whole tile is because there are many different tiles they have to take into consideration when making the farm graphic. It has to go on all sorts of coast lines that eat up part of the space. I.e., you don't want the farm to look super-imposed ontop of water in a grassland square that is along a coast. You don't want the farm to be super-imposed ontop of a river graphic either on squares beside rivers, etc.