Actually I have had very few problems to complete the Crucible, but I have seen many people asking to reduce the difficulty, although, you can not do that directly, I thought it would be a good idea to add an option with which we can ban the heroes that have caused us more problems before. It can be 1 or 2. If you think this could help a lot, we could put a price on it, it could be 10 diamonds or 200,000 coins, to balance the situation. I think it would help a lot to those who have problems.

Unfortunately, Crucible Teams were set by the Arena Defense Lineup. Can't do anything about it
But I will ask Sumoon if there's anything need to be balanced with (Like reducing the numbers of stages needed for COF to complete dailies)