I dont think abusing villagers for resources is very fair. actually i don't really care if it's fair or not i just think it's overpowered and not a very good game mechanic. so i'm going to start fixing that because im sure there's SOMEONE out there that agrees with my very controversial opinion. I've seen several packs removing drops from iron golems and nerfing iron golem farms, but they never seem to really provide the player with a good alternative. but i think i've come up with a solution of sorts, and it all stems from minecraft's fifth most forgettable yet annoying mob, the silverfish.

this pack drastically decreases the amount of iron dropped by iron golems, but adds drops to silverfish that allows new mob farms to be created centering around their spawner. with this pack, silverfish will:

• have a three out of four chance to drop 0 - 5 iron nuggets.
  
• have a one in four chance to drop an iron ingot instead of the nuggets
• have a one in one hundred chance of dropping either a silverfish spawn egg or monster spawner, with the spawn egg being dropped twenty out of twenty-one times and the spawner the other times.

i believe this is a fairly reasonable solution to the iron golem farm dilemma, albeit a slightly unusual one. just set up a silverfish farm from the spawner that generates in stronghold portal rooms and wait for one to drop a spawner. this spawner can then be placed anywhere else in the world to produce more silverfish, so although the original farm may not have been as efficient as the iron golem farms, given enough time you can create one that is vastly more powerful than the original, without driving any villagers to insanity in the process.