Maybe there is a middle ground between paying stubs and free. For example, a Showdown that costs 1,000 stubs the first time to enter only cost 1/2 (500 stubs) the second time around and 250 the third time. This helps out repeat offenders who get bounced.
Or more simply pay the first time for each Showdown, but it is free after that. But if a Showdown is successfully completed, there are no rewards for subsequent attempts.
I would also like to see a Showdown option that works like BR where both the user and CPU draft squads and then play 3-inning games until one is eliminated after a set number of losses. You can choose the difficulty for the reward tier.