I like many here also have an iPhone 4 and also have the same issues. I went to the Apple Store and they actually claimed it was a hardware problem, even though I had zero issues with my phone until the upgrade to iOS7.
I have tried the following to no avail:
- erase and restore from backup
- erase and set up as new phone
- reset all settings
- reset all network settings
I haven't tried anything to do with animation because those options don't work on the 4 anyways.
A new upgrade to iOS7 was released today, but I bet you it's not going to help this problem. I am very disappointed with Apple since they have always been helpful and accomodating to me in the past with all of my Apple devices, but not this time. I am pleased now that Canadian cell phone contracts can't be longer than 2 years since that is how long Applecare lasts and how long an iPhone generally lasts anyways. Lesson learned: if you have the oldest model "supported" when a new iOS is released, DO NOT upgrade!!!