Seems to me it adds three series compared to GSL? (10 for GSL, 13 for 8DE)And also we get a huge and kreygasm amount of very high level games and it only adds two series in comparison to the gsl format but has higher level of matches guaranteed.
I actually think two 8 player double elimination brackets with 3 players advancing would be more interesting, as there is a bigger advantage for the winner bracket (straight to semi's instead of quarter) and it should offset a group of death a bit more. Logistically it also makes a bit more sense, as you don't need to have 5 series on a single day or be forced to split them over 2 days (you can drop the Loser bracket final from your picture)I gotta say I am in love with 2 8DE brackets now with two players qualifiying for the SE semifinals after.
The first two rounds are identical to the gsl groups but it is guaranteed that there are no repeated matchups before the finals. And also we get a huge and kreygasm amount of very high level games and it only adds two series in comparison to the gsl format but has higher level of matches guaranteed.
I also feel it makes player want to win every game because it will give them a good advantage while losing in first round of GSL feels like to be revertable in the decider match again totally.
If you compare that to the GSL system, there's pro's and cons to both of them. As you said, there's no repeat matches and I think the players will get ranked a bit better as instead of dividing the 8 advancing players into two groups (1st and 2nd place per group), you'll now have 6 advancing players in 3 groups (1st, 2nd and 3rd place per group).
Your claim that we'll see some very high level games is true of course, but it takes away some of that from the play-offs, as Quarter finals are entirely eliminated by your method, or halved by my suggestion. I personally like it that the level of play get's higher and higher as we progress through the tournament, so for me the group stage is merely leading up to the real thing: the play-offs. Therefore I prefer the GSL format, as it will give the best build-up to the play-offs, instead of taking something away from the play-offs.
Logistically, I'm also unsure how it would be streamed. Assuming the first two rounds will be streamed similar to now with the GSL stage, this would mean that for the last weekend there's 4 series remaining with my suggestion and 5 with your suggestion. If you stream them on the same day that might lead to some problems with players playing multiple series on that day. It will be much harder to make a schedule that won't be unfair to one of the players, as you don't know who will advance and some players might be forced to play multiple series in a row or play at a really unfortunate time.
Spreading them out over multiple days might be better for the players, but not as good for the casters/viewers, as there will "only" be two or three series.
All in all, I think both methods are great, and would definitely like to see either your or my suggestion get used for a future tournament. Not every tournament should be GSL, so I would love some variation between GSL, Swiss and 8-player DE brackets.