Reshuffling, in principle, is a good administrative practice. It allows a president or an appointing authority to periodically assess his or her team and make changes where necessary. The changes can be in the form of retaining, reassigning, or bringing on new team members. How and when it is done, again is a matter generally left to the discretion of the appointing authority, the President. However, an appointing authority may face calls from both within and outside of government to reshuffle. And there were calls on this President to reshuffle but he managed to deflect those calls until today.
Whatever the motivation in terms of the timing, it is a bit unusual to see a major reshuffle with only about eleven months left in office. Politically, if this had been done a year or two ago, it may have allowed the administration to win back some of the good graces it once enjoyed at a high level from Ghanaians as seen in Afrobarometer Round 7, 2017.