IGN: With Maul, I felt it was a bit like you approached Boba Fett. Maul got rebuilt, he got back his sanity and focus – but he still wasn't quite Phantom Menace Maul, flipping all over the place – and he didn't have a double-sided lightsaber. Was that something else where you thought, "He can't just instantly be that badass again"?
Filoni: Definitely. In my opinion, he did really well for being out of the business for about ten years. To come back in and take down Obi-Wan, leaping around on velociraptor legs, he did pretty good. It's an interesting dilemma having him on these weird legs, because he can't instantly fight in the style that you remember Maul fighting in. So Sam really had to bring it through voice and through expression of animation in the face. But there's some twists coming up for Maul, that's for sure. He's far more cunning and well-trained in how to be a Sith than people think. He's not just all about being an enforcer. He got a good education from his master, and we're going to put that into effect next season for sure.
Then this from Sam Witwer (stated right in front of Filoni), regarding Revival:
You see in the episode we just saw he's getting back to the guy he was in TPM, but he isn't even quite there yet...
...There has to be a physical cost and there has to be a mental cost to go through this.
Interviewer: And what's really interesting is how he echos Vader a little bit..
So you see the creators of TCW have made their intentions clear. That even unto Revival (after Opress's comments of Maul's power growth), still Maul isn't quite at his TPM Level of combat effectiveness. Certainly not at the time of Revenge.
It's only after he got his more humanoid robotic legs in Eminence that he's getting back into tip top shape. Certainly by The Lawless and Son of Dathomir he's =/> TPM Maul. But not unto Revival.
In those videos that have been removed Filoni confirmed Maul simply did not have his TPM Mobility whilst he had those chicken legs which effected his combat performance, and that he was still in recovery at that point (reflecting Witwer's comments in front of him on Revival Maul).
Authorial statements are irrelevant in any story given that characters may change over time.
__________________ RealistRacism: "Sheevites, much like the Banites, were meant to increase in power with each member. From Lightsnake to Gideon to Azronger, this was supposed to be the case. However, knowledge must've been lost in some kind of Gravid-like incident, as Az turned out to be a mid-tier debater with a sub-par track record, sh!itting all over Tempest's legacy. Sad."