As seen in Margougou v DracKeN in game 3 of AoC Classic, the latest patch moves the pasture collection point close enough to the outside of the pasture’s area that vills standing towards the outside of it can drop off at a neighbouring mill almost instantly, with zero walk time. This is counter to the intent of the patch moving them outside to reduce efficiency.
At least now it requires a mill with a bit of luck.
So there’s a quirk that makes it beneficial to place pastures next to mills/TCs. Still somewhat RNG based, but it does seem like being affected by RNG is one of the quirks of pastures.
Is it ever significant enough to justify building an extra mill for drop off? I doubt it, but I’m not going to any effort to find out.