I was playing Terraria when suddenly I got the idea of Terraria for iPad and other tablets.
There would be arrow keys to move around, a jump key, and a button that opens crafting and inventory. You would touch the item you wanted to use then you would be using it, for example, if you were using Vilethorn and you wanted to use a Gold Broadsword you just touch the Gold Broadsword. Touch the screen to use whatever you where holding.
Here is what I think. (this is made in gimp2 so don't do anything critical about it) (below)