I think DD has a ton of variety in game modes but I'd like to see another way to play with your full squad online. I love RS but that's the only place to put your whole team together against someone else's.
Your idea for a playoff within the series you finished in is a really, really, great idea. Especially if they made it into a stamina related best of series for the last two players. Could even host a stream of the series with sponsors or commercials to donate to charity/pad SDS profits/allow them to have literally any player license.