What you suggest, @Kameleonic, could change the outcome of a round. It could also change the balance between squads and fleets. F.ex. it would be easier to reduce the power of a squad since you have lots of characters to throw at it until it's weakened enough for you to beat it, but it would be harder to reduce the power of a fleet because you don't have many extra capital ships. Neither would be fair. Your opponent invested in that"unbeatable" team. They deserve the advantage.
If you want a chance at beating those "unbeatable" teams you should learn how to counter them and build the counter
teams. If you want a chance to beat those "well-rounded rosters" you should improve your own roster.