I never did understand why the farmers got such a poor deal if you were connecting to a farm that already had a barn in place
It actually is quite easy and rewarding, to connect a few farmers to a barn farm. And the points you can get from this are huge, once a barn farm prospers, and doubles even in a game with pig. So I would not consider this a "poor deal", rather powerfull.
I agree with Hounk here. It's not often that a farm with a farmer is accidentally connected to a barn farm. It's usually a deliberate strategy to try to place a farmer near a barn farm and connect it to get some points and your farmer back. If this move was worth 3 points per city it would be too much. As it is, getting two points per city by adding a pig and doing this several times can give you many points.
I agree with this. I've definitely used the "attach and bounce" strategy multiple times during a game, and you can get some pretty solid points as it is. If you got the full 3 points each time, it would be abuse. There wouldn't be any point to claiming cities and roads.
Edit: Also,
I have adjusted the charts from Big Box 3 and put them in the upcoming CAR. Which might be coming out next week. Maybe.