I have an Otterbox Defender on my 5.
I don't have any issues with it being too bulky. I never use the clip on case, I always carry it in my pocket.
As far as apps- Wow, way too many to list here. Real time weather maps were why I got an iPhone 5 years ago.
What are your interests? Funny/comedy? Web streaming radio? Navigation? Remote control of home security? Internet? Hunting/fishing/outdoors? There are countless gaming apps. News? You get the picture. Search the App Store for what your interests are.
The features that can be done from your iPhone have grown exponentially since I bought my first one.