I for one like GW and use it to test the frogginess of my TW teams. Just a suggestion:
1. Allow us to sim individual battles so we can skip the easy ones and fight the hard ones; and/or
2. Add a button for GW Hard mode that allows us to choose basically higher difficulty battles throughout. Keep them simmable, or dont, and add a small extra reward. Or just add a single extra bonus node that is not simmable that unlocks at a certain level\power and has a top 100 arena team or something similar.