I think the knockout rounds are great examples of what a 1-and-done bracket would look like. Knockout games are always a blast, so imagining a whole playoff like that would be awesome! And we can get the "upset odds" by just looking at mls's knockout round upset stats. It would change because there would be more seeds involved in these knockouts, but at the end of the day I don't think it'll change it too drastically.I think it will lead to more games like leg 2 in SKC vs. Portland, which would be amazing. Too many first legs were either blowouts or teams trying not to give up too much before getting to leg 2. Often led to boring, unexciting footie for half the playoffs. 1 and done will force teams to go ham or at least offer more going forward, to create better games overall. Better games = more interest.
I don't know if it will necessarily decrease upsets, as home teams will be more likely to get beaten on the break if they don't do anything with their home field advantage.
and yeah better games = more interest = more people watching/spreading the word = more tv ops = more exposure = ...you get the point