Would Swiss Stage style be better for Kickoffs instead?
Nah
Swiss is, per its design, non eliminating
This makes it great for group stages. Its by far the most "game count -> correct ranking" efficient system (of the traditional formats).
However for kickoff we dont need a correct ranking. We only need top 2. In that case running a non eliminating format is just hugely inefficient. We dont care if a team is 8th or 12th; theyre not top 2 so why waste games on them?
So you want an eliminating swiss system. But at that point its just a single/double/whatever elim bracket, except its harder to understand since matchups are drawn after every round.
For group stages it'd be nice to see though. Means you can run 2 "full" group stages, rather than having to split it like last year. Plus the average game is much closer. (But then the problem is that running a playoff after is counter productive, so you kill a lot of the hype. If peeps get used to the format it could work though)