I have a temporary fix:
(this is for ios 6)
Fix 1:
1. have both settings and minecraft PE open (check by pressing the home button twice and close other apps by holding down them and hitting the minus button - dont worry this will not delete your apps)
2. Go into settings and make sure wifi is switched off
3. open minecraft and hit play but dont open any worlds
4. double press the home button and go back to settings but dont close minecraft
5. turn on wifi and connect to your hotspot
6. If you want to connect to an already open server continue reading 6 otherwise go to 7. Once gone back into minecraft after wifi is turned back on wait for the world to appear and click it - it will take up to 2 minutes before it will actually join into the server. - be patient
7. if you want to open a server and you have turned wifi back on select a world to open or create a new one. Both ways it will take up to 2 minutes before you will be able to play on the world and people will be able to join onto it. so dont worry if you press generate world and it freezes, it will eventually create it
8. Your finished and you will have to do this each time if your game continues to freeze
Fix 2:
1. follow question 1 in fix 1
2. when your in settings make sure "ask to join networks" is on and then click the arrow next to the hotspot your tying to connect to and hit forget network
3. double press the home button and click on minecraft and when a box pops up saying select a network click your network and put in the password (if you have one) and wait a few seconds select one of the servers there. When you select a server it will get stuck when you press it - dont worry, it will take up to 2 minutes before you will join onto it. Or you can create a new world but it will get stuck at generate world; just wait a few minutes and it will work
Note : You can only have up to 5 people on a minecraft PE server at once
same for me