For the Harvest Farm set (which seems to be the model for this one) the 1x3's had 3 bonus levels and the 2x3/2x2's had 2 bonus levels. If they did that here with the 3x1's having 3 bonus levels and the others having 2, the road wouldn't be problem.
LIkely this is being done to triple-avoid what they likely consider a mistake with the fall set's wheat field:
Scene: Event Development meeting
What could we do to fix this with a similar set?
- we could nerf the bonuses
- we could make it require road
- we could add a 3rd connection required (though technically the 3rd connection is only for 4 goods, so most people would be willing to skip that one)
Done, done, and done. Ship it!