Here's a couple of suggestion I have for the banner system:
- Tool tips on mouseover
- Have different banners for higher kill numbers; for example, for every 50 mobs killed, have a different border on the banner. The first banner is normal, the second would have a copper or tin border or header at the top, the third would have iron or lead, all the way up to chlorophyte, following the ores of Terraria. Maybe even increasing the number you have to kill between banners as you get higher.