Odd shapes and constantly starting/stopping the plougher/seeder/harvester mean you get less ROI on your equipment. Farming is super tight margins - if your machines waste 20% of the time starting and stopping every time they pass over a road, your farms profits are wiped out.

This is true whether the machines are robot driven or not, and it's the reason most commercial farms have huuuuuge fields rather than lots of small ones.

Why would the access roads create a complex shape? Fields already have access roads. Either the farm is flat and the turbine access roads can be on a minimally invasive grid or the turbines are on a hill and the fields are already a complex shape.

The cost of the land to the grower is lower on account of the presence of the turbines.

I have trouble imagining that the cost of interrupting your seeder or lifting your plough every quarter mile is really higher than the profit generated by the wind turbines.