We have done WWTB several times now, once with our oldest ds and now again with our middle ds. It is a challenging writing program that is well worth completing. I partnered with my dc the most in 2 phases of WWTB. The first phase being the prewriting/planning stage. Helping my dc choosse a topic they knew quite a bit about, and helping them map out a structure and sequence for their writing that makes sense were very important. They were not good at this at first especially, and my discretion and guidance was really needed for them to be successful. The next phase, where they used their plan to actually do the writing of their piece, was a phase I helped less. This was done more independently. In fact, I often reviewed their prewriting/planning notes we'd done (all following WWTB's mini-lessons), and then I'd purposely leave the room for a bit and leave them alone with their thoughts to craft their writing piece. Their first attempts were pretty factual and not all that flashy, but due to our good planning previously, they made good sense, had a good sequence, stuck to the topic, and had some interesting parts.
The editing phase was the next part that I helped quite a bit. I had them read aloud their writing with pencil in hand, so they could change, add, edit portions that didn't make sense or could be worded better. Their changes were minimal at first. After helping make rudimentary changes that were obviously necessary (i.e. grammatical, spelling, etc.), I then used the WWTB guidelines to help them add in any other missing elements. I didn't do this like they 'messed it up,' but more like - 'hey, this is a great piece of writing, now let's add some flash to it.'

I challenged them to use 3 big vocabulary impress me kind of words somewhere in their writing to sound like the 'pros' they were trying to emulate. They got better and better at this. Once they figured out I was going to help them but then also hold them to the standards set forth in WWTB, they tried to do these things earlier on so there wouldn't be so much to do later. Riley, who I am working with now and in the final month of CTC, will often tell me he did this, and this, and this, and this... just like the WWTB told him to do.

He'll point out his impress me words too. Sometimes they are impressive, sometimes not.

But, they are a vast improvement!

Not every assignment clicks with every student, but all are excellent lessons to learn and skills to hone.
I really like LynnH's advice, and I think her friend's comments about helping dc along with their writing are right on track. Imagine how different these lessons could be if your dc viewed you as partnering with them over some cups of hot cocoa and whipped cream?

Taking on the persona of the encourager and partner by offering guidance is such a great role to be in - one that you will enjoy and one that they will come to appreciate given time.

I'd not switch programs as WWTB is an excellent writing program, and as WWTB 2 is another excellent writing program planned in MTMM. Also, I agree with Tidbits of Learing that Igniting your Writing is a good writing program. I did want to mention that HOD chose "Igniting Your Writing" for those families that are not doing a core guide and needing a general writing program to partner with DITHOR. The writing programs for each core guide are chosen carefully for that guide's age range and within a hierarchy of skills from guide to guide, as well as to keep in balance the other LA skills written into each individual guide. It's nice to keep that carefully planned balance intact.
As far as the written narrations, I noticed that dd is 8 and turning 9 yo soon. She'll be in the target age range for CTC very soon, but even then on the very young end of it. I think it is completely fine for her to answer the questions to compile her written narrations at this point. As LynnH said, helping her add some creativity to them and also helping her begin to add transitional words to help it flow and not be choppy will be good goals eventually. My oldest ds was 9 yo when he did CTC, and he did the same thing as your dd. He is a wonderful written narration writer today in his WG guide, so take heart! Creativity will come.

For your ds's written narrations, it sounds like he is doing just fine. I hope something here helps!
In Christ,
Julie