Thank you for such a detailed response! We are glad you had fun with the game, you are welcome to come over to our discord, we would love to hear what builds/heros you were using and how far did you get :)
You have some interesting suggestions here, and you are right about all of them, indeed normal runes need some more work, unique items don't transfer to summons at the moment, "pay to refresh shop"- great idea. We are already working on the next update that might include some of your suggestions :)