With the change to farms so that bonuses now add only +0.1, it's probably more useful to put the city in that spot and grab the 30% pop cap bonus. That way you need less city tiles and can use the extras for farms, where the +1 food base from a farm is big for food now.
I didn't like the change at first, but realized after a while that in real life, farms don't really care about what's next to them, but cities do. Now I worry about farm placement only to ensure that they buffing some cities.