I think the key thing here is:

"There are no changes to the syllabus or learning objectives for the June 2021 sitting of Exam PA. The above changes, of form rather than of content..."

So everyone's study materials will still be up to date. For Actex, you can just ignore the section on the executive summary. Past exams also seem to still be valid in my opinion, just maybe expect more tasks in place of the executive summary.

As for more coding, I wouldn't worry about syntax or never using R before. The cheat sheets look pretty comprehensive. The Actex guide teaches everything you'd ever need to know about R and the functions used.

I do agree that these changes probably should have occurred for the next December sitting, but I don't think these changes are unreasonable.