Every tablet I have ever owned (iPad 2, iPad 3, iPad mini, Acer Iconia, Nexus 7 2012, Nexus 7 2013, Nexus 10) has had this characteristic...depending on what you are going. I measured the back of my 3nd gen iPad get up to 116DegF using a laser temp. So, bottom line, this is a normal thing. You cannot beat physics. If you run the device hard things will warm up. Tablets all have passive cooling meaning there is no fan inside to move the heat out. So, it gets moved to the case. The iPads are made of AL, which is a good thermal conductor, so it helps get the heat out (generally speaking, heat is the enemy of electronics). If you don't want to feel the warming of the body, but it inside a case (I keep all of my iPads inside a case anyway to help resale value).