Firstly, I really like the Boss Rushes that come by every now and then. I was thinking, maybe every like 2 or 3 weeks they could make a boss rush. It would allow content creators to create new nodes that they think the people would enjoy and also allows for Kabam to get ideas on new nodes from these content creators. It would also be refreshing for the community to have different battles with different nodes.
For rewards there could be the usual 10k 5*, or cut it to 5k 5* shards because it would appear every two to three weeks. I am not a Cavalier yet so I'm not sure what would fit them, but maybe like 3k 6* shards? They could also add a couple of heals/revives to help people with Act 6.
This is just one of my ideas; people can add on/change some parts.