Honestly, I don't necessarily think it would help to anyway. Ironically, one of my farms has well over a few hundred neighbours, and it runs the smoothest or without much error than those with less than one hundred. I can almost confidently say now, it could not be a neighbour issue of any kind and that lowering your list of neighbours wouldn't help much if at all with these connections issues. See post #80 on page 8. Beware though, it's very long.
I mean deleting neighbours would help with the lagging potentially and help getting kicked off the game, especially deleting those who are high in level or has too much things out, but I don't (personally) believe it would help getting actual connection to the game any better.