You're confusing skill with your personal taste. Chibnall has plenty of writing skills, demonstrated both outside and within Doctor Who. You just don't like how he chose to write.
Two things wrong with this statement.
-RTD only did rewrites on shows he was the showrunner for. He was never involved with rewrites for SJA scripts or Torchwood scripts, at least not the first two seasons.
-According to The Writer's Tale Chibnall was one of the writers whose scripts RTD never did rewrites for, just like Moffat. If RTD never did rewrites of Chibnall scripts when RTD was himself the showrunner of Doctor Who, he most certainly is not going to do a rewrite on a Chibnall script when Chibnall himself is the showrunner.
I don't even understand what was so "skillful" about the multi-Doctor scenes. It was all pretty typical Chibnall as far as I could tell.
The skill bit was me going for a football commentary style, flavour of the day and all that — the only skill shown that seems not usual for Chibnall is noticing or respecting continuity (Adric, brave heart, veiled reference to the first time Ace left the Doctor in the NAs) and was not — in this instance — making reference to his skill as a writer. Although…
Regardless, my point is that those moments do not feel in keeping with his previous style. Although they do in the ‘regular as clockwork’ frame of thinking — a tiny character beat interrupted as stuff has to happen. And of course in that quite often the moments that follow are shall we politely say homages to earlier things.
In terms of RTD and rewrites, he’s done uncredited work for BF on Torchwood I believe, and since he’s showrunner going forwards I can see him making a few requests or suggestions (like Moffat asking for Jenny to be kept alive I believe, though he never did anything with it, unlike River Song) to help the handover. Especially as we are heading into the sixtieth.
They don’t feel like his usual work, without getting into whether or not his usual work is any good or particularly skilful. (The general consensus probably still has him being Pip and Janed to the post though… )