No user is going to understand the difference between WPA/TKIP and WPA/AES. We should simply pick the best choice and not complicate the setup process for the user. This is not a security issue (i think) but a usability issue. Neither Android or iOS ask these kind of questions.
Or if we do want to keep both these options, we should rename them: WPA/TKIP -> WPA Personal WPA/AES -> WPA2 Personal That is also the terminology that is used on OS X and Windows.
You can use WPA with both TKIP and AES, same goes for WPA2, though some standards require AES for WPA2. It would be most secure to use AES as standard for both, with a fallback to TKIP.