Sounds like you need a dedicated server old chap.

Ran on one with 6 of us for several months admittedly it was rare to have more than 4 on at time but only issue any of us had was the perennial world save mega lag paralysis.

Not disputing your poor experience just sayin' its not all like that. But yeah we ALL agree the game engine needs an optimising pass in the worst way, however the "Moooor COntnet Naaaooow!" Brigade will likely shelve that leading to the endless cycle of more but less playable content ad repetius ad nausioum