Sony Xperia Z1 Compact Specs

I am a Sony fan for almost 5 years now. I have used Sony G502 for a couple of years and then used Sony Hazel J20i and Now I am using this Xperia Z1 Compact. I bought it as a deal for 350$ and initially I was very happy with the purchase.
I loved the camera(Only at Day light) as that's the main reason I bought this. It really feels nice to have a Small kinda phone.
After using it for about six months, phone tends to become to slow, over heated while charging, low battery life, late responses to touch and even getting struck at some apps.
Mostly phone gets over heated while using data(not for maps, just for messaging) on travelling and tends to discharge so quickly. I really hate when it gets discharge without even using it for navigation purpose.

I am a Xperia Fan, had most of them for everyday use, but this one is the best for me. I have this one the longest and i know why. It rocks at everything. one thing I dont like is the screen to body ratio.

I bought the phone for two reasons, the camera and the apparent waterproof capability. Unfortunately those seem to be the main things I have a problem with.
Camera is ok but freezes more often than not especially when needed, I have tried several things safe mode etc nothing seems to help, night shots are poor and I feel as though the camera quality has been over exaggerated to promote sales.
Waterproof after reading no end of forum messages and complaints it would seem a lot of people have had damage due to water, I also read the small print it is only water proof in fresh water so this is definitely not the phone to take to the beach.
If I could change this phone and get my money back I'd happily get my galaxy S3 back and buy a Go pro :-)