The official Samsung Galaxy Alpha Qi wireless charging cover is a form fitting cover that can be used with any wireless charging pad to charge your Galaxy Alpha wirelessly. Since the back cover replaces the original back panel, it adds very little thickness to the sleek Alpha.
The main thing that is of concern other than making the profile less flush is that the Samsung logo on the wireless charging cover is matte and flat like a cheap plastic print which is not at all in keeping with the quality of rest of the phone. On the standard cover, the Samsung logo is shiny and embossed.
So why is it thick. Well they have to place the coil somewhere – it is just a sacrifice you have to make for having the convenience of wireless charging. However I would say on the Samsung Galaxy S5 the gain in thickness is almost not noticeable. So I still feel the company could have made it thinner.