You are free to play however you want, nothing is really mandatory.
However, why not opt into choices which improve your raid performance (more healing, Damage, Survivability) vs those who don't.
This is what I found:
-Enchants for your Gear
-Flaks, food, Potions
-Garrison Buildings for Gear and Asphexis Crystals = Valor
-Health Tonics (Crafted by First Aid or purchased from the Auction House) - Heal more than Healthstoens or Potions and have an own Cooldown category.
-Racials for some Specs. (Racials are closer now, but some are still worth more, such as Crit Racial for Fire Mages > Haste Racial, or Crit Damage Racials are better than others for Specs with Guaranteed Critical Attacks such as Frost DK, Destruction Warlock, Elemental Shaman etc. There are also Racials which benefit Tanks so you are better off picking a Race which has them vs. a Race which does not, like Nelf awards 2% Dodge vs. Worgen which gives nothing in terms of survivability)
-Weekly bonus Loot quest - Thanks, Zenway
Now it is your, the MMO Champions', turn to enhance this list. Maybe some aspects were forgotten or became obsolete by now.