My suggestion would be, have a ton more weapons and armor. Make some over powered but the drop should be like point 1 percent.
Make this game subscription and drop content on a regular basis. I'll pay for dlc and subscription if it means new mini raids every quarter, new missions every month, more weapons and armor, more customizable characters and etc.
I can't say I haven't gotten my money's worth, I have buy I think this game can be much much more.