marking as spoiler as precaution
Amongst the rumors is that we will get an Obi-Wan vs. Vader rematch.
Now obviously that is a ratings boost right there.
However all novels and comics over the years, be they Legends or new Canon, did not as I recall have a rematch between the two.
Ep 4 implies that their fight on the Death Star IS the rematch after Vader was fried and becomes a cyborg. Never specifically stated, but implied.
To have a rematch in this new series of course would please many fans and I am sure the will go for as much combat and carnage as possible in the rematch, but they still need to account for their fight in Ep 4 on the Death Star.
Thus a rematch would likely end with some type of a cataclysmic ending such as an explosion that leaves Vader injured both organically and mechanically but he thinks Obi-Wan is finally dead.
In Ep 4 after the Falcon is captured and found to be empty, Vader dimly and briefly senses the presence of Obi but dismisses it at first until later when he speaks to Tarkin and is convinced Obi Wan is aboard. Tarkin believes Kenobi is dead, however the report of the Princess being rescued is what convinces Vader and he goes to find and duel his former friend and former master.
That IS the downside to this upcoming series. We already KNOW Obi -wan will survive whatever is thrown at him, including a Vader rematch until the events of Ep 4 where he finally gives himself to the Force just before Vader cuts him down. Just like we know that whatever adventures and problems Vader has he is going to survive until Ep 6.
I do look forward to the series, but at the same time I am having some trouble getting overly excited as it is a prequel series that is being made YEARS after the first 6 movies.
That will be this series major weakness.
Mandalorian and Boba Fett are both 5 years after ROTJ but they aren't quite bound to the events of the sequels as they are still years away and rumors abound that Star Wars may under go some "temporal revisions" in the near future that might revise or negate the sequels. (we hope!)