Let’s go the opposite route and discuss things we don’t miss and glad Blizz “got rid of it”.  I’ll start:
I don’t miss low count stacks of 10, 20 or even 200.  Glad we’re able to stack our profession materials up to 1000, now.  Love the extra bag space 
Your turn.
             
            
               
               
              29 Likes 
            
                
           
          
            
            
              When the mailbox took an hour between guildies!
Also, Oribos (it’s not deleted but I don’t miss it mwhahaha)
             
            
               
               
              24 Likes 
            
           
          
            
            
              One time I fell asleep while driving and I did not miss a whole bunch of trees.
             
            
               
               
              14 Likes 
            
           
          
            
            
              What ever the main hub is SL was… absolutely a disgrace of a city.
             
            
               
               
              7 Likes 
            
           
          
            
            
              
 Rita:
 
Also, Oribos
 
 
Oribos reminds me of the passenger terminals at DFW Airport. Maybe they were leaning into the whole transit hub thing?
I don’t miss it either.
             
            
               
               
              7 Likes 
            
           
          
            
            
              Rune of Power. Good riddance.
             
            
               
               
              17 Likes 
            
           
          
            
            
              Needing the blessing of salvation in raids.
             
            
               
               
              3 Likes 
            
           
          
            
            
              single-tag mobs and faction tagging.
That was a real pain in quest areas with limited spawns.
They can still go grey in crowded spots nowadays but you have a better chance at least.
             
            
               
               
              20 Likes 
            
           
          
            
            
              The systems overload of the Legion through Shadowlands expansions.
             
            
               
               
              5 Likes 
            
           
          
            
            
              …i’m scared of this monkey’s paw affect if things get worse. 
             
            
               
               
              3 Likes 
            
           
          
            
            
              Hunters everywhere are gonna hate me but . . . ammo.
Being in the middle of Karazhan and forced to hearth to get more kinda sucked.  A lot.  I do not miss it.  And hunter was my second toon, an orc hunter I made when vanilla Naxx was current.
             
            
               
               
              13 Likes 
            
                
           
          
            
            
              All it lacked was a Cinnabon and a thousand bored TSA agents.
             
            
               
               
              5 Likes 
            
           
          
            
            
              
I don’t miss that on my hunters either.
Also having to feed your pet to keep it from abandoning you.
(Yes I still feed them but just cuz)
             
            
               
               
              14 Likes 
            
                
           
          
            
            
              Shadowlands convenants, legendaries, and the grinds related to them
             
            
               
               
              1 Like 
            
           
          
            
            
              Ammo for Hunters
Reagents for raid buffs like BoM and BoK.
Rogue poisons.
             
            
               
               
              7 Likes 
            
           
          
            
            
              Weapon skill leveling 
Ammo 
SoulShards (item version) 
Crafting Poisons 
Not sure if I miss feeding your pet, it was dumb that it left if you didn’t 
Portal Reagents
I’m sure there is more
             
            
               
               
              6 Likes 
            
                
           
          
            
            
              40 person raids that needed insane attunement just to get in.
             
            
               
               
              7 Likes 
            
           
          
            
            
              
All of these except maybe weapon skill I miss from the sterile game retail has become.
To the OP item stacking is definitely a huge one for sure to me.
             
            
               
               
              3 Likes 
            
           
          
            
            
              
Onyxia is the only one with an “insane” attunement.  Some quests and a few dungeon runs.
MC - do 1 dungeon 
BWL - do 1 dungeon 
AQ - no attunement 
Naxx - pay some gold.
             
            
               
               
              3 Likes 
            
           
          
            
            
              
 Estalayia:
 
I don’t miss
 
 
Looking like a Skittle when I get new gear.
             
            
               
               
              14 Likes