I had responded to this post earlier but got a Bad Gateway request! I think it's a very fair post, however I'm not sure that they did not want to follow the books more, I think given the choice any fan of the books (which Rafe is) would want to ensure as much faithfulness to the source material as would be possible.
But to answer your final point on the reasoning, much of Rafe's comments around creating the adaptation has focussed on telling the story of WoT in it's entirety. Even his post addressing the cancellation of the show mentions this - "One of my core goals in making this show, even from the earliest crafting of the pitch, has been to tell the whole story".
I think they took the view in adapting the books that they needed to lay groundwork for the epic conclusion of WoT very early on. That meant showing us a lot more Aes Sedai politicking for example than we got in the books, or at least showing it "on screen". We see a lot more of the internal Aes Sedai divisions, and establishing how the White Tower would come to try and cage the Dragon for example, setting up Dumai's Wells in future. The Stepin episode was clearly to set up what happens to a Warder when their Aes Sedai dies - potentially establishing the danger for Rand further down the road.
I think this driving factor really was behind the vast majority of adaptation choices, in that they were trying to make sure that the ending would really "land" so to speak.
However, I think they may have gotten a bit lost in that big picture thinking and didn't spend as much time establishing the characters which drive the entire story. I said in the show cancellation thread that I think the big picture focus is good generally, they have to get across so much in the world of WoT in a limited time, so spreading the love is a good idea. And I liked things like the Stepin episode as a bottle episode almost, to show TV audiences how the Warder bond functions. However, given the choice to establish the EF5 more versus what was a very good episode on it's own, I would choose the former, especially early in the show.
As it was, while the show improved and S3 was the best so far, I still think it suffered from not developing our main characters. I think very often they spread their focus too thinly and it was no coincidence in my view that the highest highs of the show was when they spent time on one character or story - Rhuidean, Nynaeve's Accepted Test, Egwene with the collar. Funnily enough, considering the issues they had with the casting, one of the best developed characters for me was Mat, as I felt it was clear what they were doing with his arc of being a reluctant hero. Just like the other characters though, I wish we had more time with him.