I don't know about you, but i don't want Pigmen running around OUR village, what will the neighbours think!?
Also, the NPC houses seem cramped, unimaginative, repetitive and lots of other words ending in 'ive'. I'd much rather build a house that looks awesome and tailors to my needs specifically than ransack a non hostile village for a shack.
Neighbouring villages on the other hand, sound awesome, as long as they're not directly next to our place.