How to get removed default app back?
No, you won't be able to get it back without a backup unless you know someone with the same phone who can back it up &amp; provide you with a copy.

You also won't be able to update your system OTA in the future either, as updates check to make sure that all the apps that should be there are present.  If they're not, they won't install.  

Freezing apps rather than deleting is generally a much better idea.