First of: Cool with a new feature and nice to have something to spend tickets on.
That being said, there are imho two major flaws to the current feature. Primarily the massive RNG and the encouragement of anti-social behaviour (or rather intra-club competition) that makes it possible for trolls to screw over the club
Both these could easily be solved by tweaking the reward system.
example:
Raise the floor to 5* shards (i.e-5-x shards for victory)
lower the ceiling to 25 shards (i.e:5-max 25 shards for victory) After the max shard reward is achieved, all effort would only help your clubmates (very slightly) improve their rewards. If the champion is not defeated you will gain nothing.
*As the rest period is 24 hours 5+% would only just be enough for active low levels to get the reward within the 1 month rotation.
There are many other ways the rewards could be tweeked to achieve the same goal, this was just an example.
I like the idea of raid-like battles but with the current setup it seems a better chioce for me to burst down the champion than working with members of my club....which is ok, but in my view hardly optimal.