A theme is just a fancy way of laying out icons and backgrounds, and using other widgets...There's a ton of options for customization. Just search the play store for Icon packs and start there.
I haven't rooted (to my knowledge, anyways), Nova Launcher is an "app" available in the playstore
I spent a while debating cases, and settled on this one. I'm happy with it-easy to grip, I've dropped it a few times and it is just fine. UAG
I got this one.
Love it! Makes me feel like Batman. Easy to grip. Buttons still respond.