Activating braille display every time
It would be nice if we didn't have to go into settings and choose a braille display every time. It should activate automatically like a keyboard does.
Do you mean reconnect? Wake up your Braille display before your iOS device. If Bluetooth is on, VoiceOver will searche for the last used Braille display. If you forgot to switch on your Braille display first, then simply lock and unlock your iPhone to force VoiceOver to search again.
For me it helped to change the timeout in settings. I set the iPHONE to never lock. Then under passcode I set it to not ask for the passcode every time I unlocked; it asks if it's been locked for 15 minutes.
This way when I forget to turn on the Braille display, something I seem to always do, I can quickly lock and unlock again without having to enter a passcode and I still have plenty of security.
Also by setting it to never lock you don't have the issue where the Braille display suspends, your phone suspends and you are suddenly disconnected. Be sure too, if the Braille display has an auto-suspend that you adjust its settings so it doesn't happen every couple of minutes.
I'd love the Braille display to activate whenever you turn it on, however the problem isn't as simple as it appears. Most Braille displays are, for lack of a better term, passive (i.e. they rely on the device to request a connection) where as most keyboards are active (they seek out the last device to which they were paired). What you have to do if you want to automatically detect a passive device is periodically probe for it at a set interval, usually less than a second. This is something that VoiceOver on OS X does, and why it is able to connect to a Braille display over Bluetooth at once. The problem with this approach, however, is that it's not really the right thing to do on a mobile device where conserving CPU cycles, and by extension battery life, is a priority. What Voiceover on iOS needs is, perhaps, a command to quickly seek out the Braille display if you didn't wake the display up before you unlocked your phone. I think that would be the best compromise, since you do not want to spend valuable battery life repeatedly probing for a device you may not find at that time. The other alternative would be for Braille displays to be more active in seeking out the last connection used as most keyboards do, however this isn't something Apple can control.