I think one of the major points of iOS7 is that grandma is getting kicked to the curb. iOS devices are designed for people who already know how to use them, or for young people, who will figure them out.
Except this doesn't seem to be borne out in reality. I have installed it for people in their 60's, 70's and 80s who find a Mac barely usable, who have had no trouble at all with moving to iOS7 after using iOS6.
I was speaking figuratively, of course there isn't anything inherent about being a grandma that prevents you from using iOS7. The point is the people who have never used a smartphone before will probably not pick up iOS7 as fast as they did iOS6 due to affordances the UI had for folks like them, which were discarded since most people on Earth have now had some experiences with smartphones.
Any change can be construed as kicking a percentage of users to the curb. I just don't think it's reasonable to hold back design for them. If they learn, great. If not, maybe it's a sign that you should be spending more time teaching your grandma.
PS. Your grandma says you never call. She knows you're busy but still, a phone call once a week never killed anyone.
