You'll soon find out that designing the armoury is a huge and difficult task.
Just make 5 sets of armor, then color them differently and make a new color for every 10 levels. Every 5 levels take the previous set and rename it Blahblah Armor +1 and ever so slightly increase the stats each time.
Make sure no armor sets actually work together well with each other, forcing the players to wear mismatched armor sets that look absolutely HELP I AM TRAPPED IN 2006 PLEASE SEND A TIME MACHINE together.
That is pretty much the system of this one game I played... I forget the name of it though.