The only issue would be how to handle loot and xp.I would play with no promise of either but some will complain if it gives too much or too little. finding a balanced way to reward players for putting so much time in will be a challenge. Im thinking higher tier drops after every exponentially difficult wave completed.
English
-
Agreed. You should get a fraction of your normal adds kill xp, and have it steadily go up as more waves pass and more powerful enemies find their way onto the battlefield. And after the first ten waves you get whatever rewards, after twenty you get whatever better rewards, and so on