I was thinking how to balance the raids a bit better.
In every cup range there are a certain amount of players.
All these players have a team they prefer to use. Based on the 6 (?) strongest hero’s you can calculate what the average team strength is for all players in the cuprange.
Just some random figures:
No cup range (<600 cups) average team strength is 1500 teampower
Silver cup range (>600-<1200) average team strength is 2700 teampower
Gold cup range average team strenght is 3400 teampower.
Now we have established the average teampower in a range we can see people playing below or above their range.
So to make it more interesting to stay where you are you can reward people that have a team that is 20% (?) lower then teamaverage with better/more loot.
So for silver; if average is 1500 and your team is only at 1100 but you still manage to be in silver, you get more rewards.
In the same way you can penealize people that are raiding below their standard. So again for silver average is 1500 and you are in silver with 2100 average teampower your rewards will drop and you will get less rewards, and thus be motivated to raid on the level you should be.
I think there might be some tweaking needed to this idea 
but you will get the general idea I am having.
So shoot and lets try to see if we can improve this idea (or conclude it is ridiculous 
)