I think it's simplier to just murder pigmen as you go in the nether.
I had one gold farm in the nether, and I was building one in the nether roof, never finished it.
I'm kinda thinking about making one more but half slabbing will be a bitch to do and you know why.
But, since I know that half slabbing helps in the long run, you can get yourself some decent amount of gold.
Or you can make a wither skelly farm that spawns both wither skeletons and other nether mobs.
Before the reset, there was a dude who literally gave me his wither skelly farm because he left CM.ΕΎ
The spawning rate was great when there was about 15 players online so make sure to focus on that.
I have some farms in the nether that I plan to do but since I have a job now, I mostly get tired as fuck because warehouses are a motherfucker to work in, and I don't know when that shit will be finished lol.
When it comes to blaze farms, I usually set up one of those noob-made ones. I surround a spawner with netherrack and I make a 9x3x9 space and let them spawn, and I kill these fuckers and get lots of XP.
My main reason for the farms in the nether is obviously wither heads and gold, but having a blaze farm won't hurt me at all. :) I'm not sure if it's possible to set different render distances in each dimension.
I'm a complete nublet in that kind of stuff but if that's impossible that's completely understandable.