But I really dont get what you want. First you say that you dont want to go back to HFC for gear, but then you want to be competitive in it? You mean for a raiding guild or?
The people who gain the most from prepatch is people who have a lot of sockets. 75 gems turn into 200 stat, which is about 50% of the stat most items give. Blizzard is also testing out their new baleful proc items (or at least it seems like they are from how the dungeon journal for HFC is looking right now). All bosses have changed to the same item level on each difficulty (705+ for heroic) and we dont know how high they can proc. But lets just assume nothing changes and this is just a tooltip bug for beta, this is how your changes should look like for prepatch (assuming we still go for haste > mastery > crit > versa).
Helmet: Tier
Neck: Iskar (changed from multi/mastery to mastery/haste)
Shoulders: Tier
Chest: You keep your current chest because there is no other option than tier and this one got a gem
Wrist: Xhul (item unchanged in patch)
Hands: Tier
Cloak: Socretar (changed from haste/mult to mastery/haste), but because this item is 10 ilvls lower than archimonde cape it might not be worth it
Waist: BoE (item unchanged in patch)
Legs: Tier
Shoes: Archi (changed from multi/haste to mastery/haste)
Ring: Kilrogg (changed from multi/mastery to mastery/haste)
So in total you are making 5 changes if you dont include the cloak. 3 of which you could get without going to HFC by crafting them and 1 which you can buy from AH.
Learning how to play your spec is going to have a much bigger impact than changing a couple of items.
Edit: Didnt they remove the ability to wear 1h's for fury in legion aswell? Better get some 2h's if they did.