The UK does not have a presidential system, although Boris Johnson seems pretty determined to change that. An important difference between the two systems is scrutiny. When we cast a vote in the general election, the public did not vote for the country to be led by Boris Johnson, we voted for it to be led by the Conservative Party. In this cabinet reshuffle, Johnson hasn't done a good job at reflecting that.
Johnson does not care about his ministers' talents, only that they know how to say "yes"
The day started off with the dismissal of Julian Smith, the previous Northern Ireland Secretary, presumably after Johnson and him clashed over Brexit negotiations. Smith had been credited with helping to get Stormont (the Northern Irish parliament) back up and running, after years of deadlock. The sacking therefore sent a clear message: Johnson does not care about your talents, he cares that you know how to say "yes".
This was shown yet again with the treatment of Sajid Javid, the ex-Chancellor, who was asked to either replace his advisers with those selected by Johnson and Cummings, or leave. Looking at the historic role the Chancellor has in keeping the government in check, it is quite horrifying to see Javid - who did often stand up and openly disagree with the PM - replaced by the more loyal Rishi Sunak.
Who will keep Johnson in check if he replaces anybody who doesn't tell him exactly what he wants to hear?
Who is meant to keep a Prime Minister with an eighty-strong majority in line? Who is going to tell him that what he's doing is a mistake, if he's so willing to replace anybody who doesn't tell him exactly what he wants to hear? This all feels like it could develop into something very dangerous, or at least profoundly stupid. Reshuffles should help promote new talent within a party, not help the Prime Minister gain more power over that party. While Johnson is far from the first to abuse the system like this, he definitely highlights its flaws.
The view in favour of the reshuffle is available here: https://www.thecourieronline.co.uk/the-cabinet-reshuffle-looking-on-the-bright-side/