It isn't a fact. All you do is change how your character looks. It is nothing to be excited about. And no, they haven't really improved it. They just added more things to customize your character. It does needs a better purpose because right now it is useless. And no, it is not a reward itself. I rather get items for certain customization so it could be more useful and serve a better purpose.
Now, you may not like it, and that is perfectly acceptable, you're entitled not to, however, there is a big difference between not liking something, and something being a waste of time.
Also, if you haven't taken noticed, they have already greatly improved it since X and Y, and we haven't even seen the full extent of it. It also doesn't need a 'better' purpose, as it already fulfils everything it is set to do. Not EVERYTHING needs to be included that gives you tangible rewards. Whether you like it or not, you need to realise that Character customisation is a feature that majority wanted, and it is a feature that majority is happy about. That is rewarding enough for itself.