Wow! Another great episode! The stage has been set! Ahsoka Vs Marrok was an amazing fight scene! Loved Chopper during the space fight. Filoni still knows how to make him funny.
As to why Baylan Skoll doesn't want to have to kill Ahsoka Tano, I have a gut feeling that it is because he knew Anakin well, and Anakin more than likely talked about Ahsoka a lot, so he sort of respects her. It could also mean that he is going to use the World Between Worlds to kill Anakin. It makes too much sense for this to be the case IMO.
As to who this Marrok figure is, it has to be either Barriss or Starkiller. When Marrok fought Ahsoka, he/she seemed to respect her a lot. If it is Barriss, it would make a lot of sense, since they were friends at one point. If it is Starkiller, it is because he found out that Anakin was Vader, and he probably feels a kinship to Ahsoka, because of the fact that they were trained by the same person. Marrok is eerily close to Marek also. It has to be someone we have already seen before, otherwise they wouldn't be wearing a mask.
Some other interesting theories as to who Marrok could be are Mara Jade, Petro (From Star Wars: The Clone Wars), and Ezra Bridger.
It could be Mara Jade because of the fact that it looks like Dave Filoni's Star Wars movie is going to be "Heir to the Empire", and if that is the case, Luke will be in it. And if Luke is in it, what better way to introduce Mara Jade. While an interesting theory, I doubt it because they wouldn't be wearing a mask, because we wouldn't even recognize her.
Petro from Star Wars the Clone Wars is an interesting theory as well. They have the same droid back from The Clone Wars series who helped him build a lightsaber, so it would be a neat surprise. Again, I doubt it because we have never seen him in live action, and they wouldn't be hiding his face. I know we haven't seen Barriss Offee or Starkiller in live action yet, but Barriss will be recognized because she is alien, like Ahsoka, and Starkiller will be recognized because Sam Witwer will be playing him.
The theory of Marrok being Ezra Bridger is more likely than the two above. Mainly because they keep talking about him, and we have seen them pull something like this before. It would make a lot of sense also, as to why he respects Ahsoka, and if Baylan is looking for the World Between Worlds, Ezra knows about it, because he was inside of it with Ahsoka. The only reason I doubt this theory, is the fact that how could've he come back without Grand Admiral Thrawn, and why would he be on the dark side of the force?
Should be interesting! Man I love Star Wars so much!
Out of a 10 I would give it...
10 out of 10