I doubt NCSoft will open Wardrobe to F2P players, it's too good of a feature / one of the best selling points of Premium. Also it's like what, $12-15 a month? That's not so expensive given everything else Premium comes with.
Those "21 benefits", of them, maybe 4-5 of them are substantial. A good chunk of them are fluff.
Also it's not P2W just because you have to juggle inventory. No one is saying you have to keep the non-mandatory costumes and notevery costume piece is a favorite / going to wear this later / can't be farmed again. If your argument is: "this is P2W", you'll never convince NCSoft, let alone anyone that you aren't just whining.
Instead it should be easier to increase inventory and bank slots, they should add ways to purchase additional bank tabs, and they should make it so the faction / mandatory outfits can be consolidated to a built-in feature (e.g. click on costume > expand > choose faction).