Bugs and poor performance in iphone 4 after upgrading to iOS 7*

Dear Apple,

After upgrading my iPhone 4 to iOS 7, I'm experiencing lots of issues.

The performance is the poorest that I've ever seen since I adopted iPhone.

Constantly, I need to do the same action (to touch the screen) 3 times until getting any response from the device.

The new effects adopted in the new iOS 7 have lowered the user's interaction and decreased the usability.

Multitask in iPhone 4 with iOS 7 is not smooth and glitches happens all the time. E.g., when you are talking via skype, receives an phone call and needs to search for a contact in your contact list to say to whom is calling you.

How to survive using iPhone 4, with all these problems happening?

It's bothering us, because we love apple devices! it's a shot in the chest!