I would love this option! That being said, I have started using the armor 2.0 ornaments to organize my builds better to keep track of what goes with what quickly. It helps a LOT that armor icons now display the appearance of that armor, making it much easier to switch items in the menu quickly
Basically I just make each loadout's armor match a different armor set. For instance my all-purpose survivability loadout has all dawning ornaments, and my thousand cuts loadout uses the vanguard dare ornaments.
It's not the loadouts option you are asking for, (that I would LOVE to see implemented in game!) But it will help organize and speed up your loadout changes a bit for now!