There are some features in Retail WoW that need to be removed. They are major reasons why alot of players left for Classic WoW.
1) Remove LFR and LFD = So people become more interactive in the open world
2) Remove Arenas = Because it gives the devs alot of headache for balancing classes
3) Remove Heirlooms = People who twink at certain levels can't compete in Bg's or world pvp.
4) Remove Titanforging = When people get bis gear, they should be able to keep it instead of having to run the instance again and again praying to RNG.
5) Make Professions Great = In the past, Blacksmiths could add gem sockets to gloves, Jewelcrafters could use Epic gems, Herbalism had a haste cd etc.