Stated costumes that non-cash players cannot obtain through in game means are what would be unfair.
Costumes in the cash shop in the Korean version are character bound. Assuming the same trend holds true here, the statted costumes you are talking about would be unfair. The current system, even with them being most easily obtainable through RNG gambling via the cash shop, allows you to sell the items that you enchant on the auction house. That means, even if it’s a high price, the average player doesn’t have to spend real money on it.
That means that you are offered a chance to get them whether you pay or not. That is why the enchant scrolls are far more fair, in my opinion. I feel like they give greater value than their cost as well. There is no +200 hp potion instead of a bonus. I think it’s a pretty decent system compared to the way that many other games approach this.
I’m not saying you are wrong, I’m simply saying I do not like that method and really really hope that we stick with what we have. Though I advocate a higher drop rate in game.