As a heavy user in Chinese text editing, I used to have 3rd-party input method with Shuangpin happily on the jailbroken iOS7 device.
Nowadays, iOS8 has all the major Chinese input method corps, like Baidu and Sogou, without the API toward bluetooth keyboard.
As a result, my productivity dropped dramatically without a BT keyboard, so were a lot of heavy users in Chinese world. And the answers were all pointed to the limitation of SDK.
Hence, I sincerely wish Apple to empower 3rd-party developer the access to BT keyboard.
With the mighty power of BT keyboard and 3rd-party input method, the productivity of iPhone and iPad will be fully unleashed in Chinese text editing field.