What you percieve as a why the game needs an appearance tab are not reasons necessarily shared by all players and BioWare. While some players may want unhindered flexibilty in their customization, BioWare seems to be making avoiding "the clone effect" and haveing the potential to make wide varieties of outifts as their goal. They avoid appearance tabs in order to retain some level of visual progression, meaningful appearances over costuming, motivation to go and gather in-game items and to consume resources and and credits. I personally agree with their direction.
Yea I could go with that reasoning if the end game gear didnt look like crud.