I do not see this suggestion working out to be honest.
The majority of these outfits already exist in the game, and very few people use them as it is as there are more appealing options, such as the Bee or Zebra clothing. They're also already accessible to everybody, and restricting what is already free content to a select group of premium players would just be unfair to those that earned these items legitimately. Introducing these rewards as a minor change in tone alongside the already existing armour sets wouldn't be very rewarding either, since most players already have what some would consider to be the better variant already, without having to purchase a rank at all.