1. If everyone qualifies anyway, what's the point of having group stages? You can just draw lots based on rating.
2. If the castle choices are different, how will it work? If there are even 4 players in a group, that's only 6 factions, which means 2 factions won't be used by anyone, and 2 templates will be discarded.
3. How will the factions be chosen in the playoffs? The solution hasn't been thought through.
4. I wouldn't overthink it; it's not that critical.
In summary, Evgen, you're essentially proposing either a different tournament or one with rules that aren't fully developed. And what's wrong with the round-robin format? It's not even certain that enough players will be available for groups, and the playoff mechanics don't really fit with this tournament format, which didn't have any issues in previous tournaments. There might even be more games with playoffs, and then some players will be left out of the tournament. The only drawback of the round-robin format is that you need to strictly monitor the deadlines.
P.S. Guys, let's indicate our preferred playing time when registering so we can coordinate when to play with whom.