I've seen a lot of statements from Blizzard about what is and what isn't exciting about loot acquisition. While I agree that getting something unexpected can be exciting it's not the be all and end all.
I can only use myself as an example but I'm sure there are some that feel the same way but just for clarity these are my opinions and nothing else. Knowing what you're after and having a reasonable chance of getting it can be just as exciting. Some of us like chasing that one item we really want, even if it's a 1% drop chance off a specific boss sooner or later it's gonna drop. Getting a perfectly rolled pair of generic gloves isn't off some random mob in the world is sure exciting but it's not really a goal you can put up there since chances are it's never going to happen.
I remember on multiple occasions back in the day when I was close to getting a PvP weapon or valor item I felt really excited on my way home because I knew that this was the day it was going to happen. You can't really get excited in the same way about something that may happen but most likely will not. It's like losing weight, it's a long journey but the closer you get to your goal the more motivating and exciting it gets.
I believe some RNG is fine. Like warforged for example, that was fine. But when sockets were added into the mix that BiS item you wanted was suddenly so far out of reach it removed all excitement from looting a boss. And it also killed off a profession and a system I felt was really good in MOP with how the sockets worked. Tweaking your gear with gems and enchants adds immersion and to be frank it has a significant place in an RPG.
Back on topic. I'm also fine with complete mayhem of RNG out in the world since you're never there looking for something specific and every surprise is a good one. It's like finding a pair of green shoulders back in vanilla during early leveling. But in dungeons and raids I feel that loot shouldn't be a slot machine, even if bosses only drop 1 item every kill and the loot table consists of 20 different items you know that one of these days your item is gonna drop. The items that stick with you, the ones you remember getting aren't the socketed and warforged Generic Pauldrons of the Feverflare titanforged to maximum, it's the Mantle of the Blackwing Cabal, it's the Tusks of Mannoroth.
I believe Blizzard are 100% wrong in their views on what makes loot exciting. In some areas of the game lots of RNG is perfectly fine but don't underestimate the satisfaction of going after a specific item and getting it, if it's from a boss drop or from farming of a currency. For me, the best part of the endgame was always crossing of items from my wishlist and that's not a realistic way to play the game anymore.
There's nothing exciting about not knowing what you might win.