There is always going to be a shift in tone when the actor changes. Lazenby aside there has always been a fairly strong contrast from one Bond to the next with Roger Moore probably being the biggest outlier in terms of who he followed, who followed him and alignment with the source material. Beefcake has never really been first and foremost and certainly not in the source materials featuring a quite bland functioning alcoholic Naval Commander.
DC is very close to the source material in many ways but veered very far away in others. But given the source material dates back from over 70 years now it would be borderline Austin Powers levels of ridiculous for Bond to be the same man. I reckon Cillian Murphy is too old for a new Bond (4 or 5 films?) and too big an established lead. It's usually someone a couple of levels down from the A-List. At the time of casting DC was probably the biggest 'film' name to ever be announced in the role.
Essentially, I'm saying give it to Chesney from Coronation St.