if your only issue is with notifications (not sure about texts), this seems like the easiest to fix, in terms of blurred screen; because you DO NOT have to have your notifications display on the lockscreen. You SHOULD be able to have them display in the notifications center swipe down; but so long as they don't have to display on the lockscreen there should be no reason for the iOS to blur the background.
there IS an option to remove an app TOTALLY from notifications, if necessary.
so maybe the only question is: what is more important: your notifications showing up on the lockscreen or your lockscreen image.
to me, i don't care where my notifications display. certainly don't need them on my lockscreen.
my main blur issue is NOT with notifications; but with audio playback; because iOS thinks it has to display the audio controls on the lockscreen, which blurs the wallpaper. But, when I hit PAUSE, I can get the screen to go back to normal (using by toggling screen ON/OFF). hopefully there is a way to remove that from displaying on the lockscreen, since the control center has the same audio controls and is also accessible from the lockscreen.
hope this helps.