Brosnan was as handsome as Connery, as tough as Dalton, his films had a smorgasbord of gadgets, and he oozed character and charisma. He encapsulated everything that was good about all the other Bonds individually and rolled them into one.
Brosnan maintains the one-liners and quips that Roger Moore had. He has the tough-guy bravado of Dalton (the opening scene in Goldeneye racks up a franchise-leading 47 confirmed kills). He enjoys the company of the female variety, much like Sean Connery, and he retains all the elegance and dignity a Bond needs. He is the ultimate Bond chimaera and, therefore, the ultimate Bond. 
Pierce Brosnan himself said that his Bond wasn’t good enough. If that isn’t a sign that something went amiss, then what is?  His performance is flat and lazy at times. He is also smug in a way that the sophisticated Sean Connery and Roger Moore never were. Brosnan piggy-backs on decent storylines and strong, well-rounded villains. His demeanour is also not tough. He doesn’t look physically imposing like Daniel Craig, and as a result, loses credibility.
[P1] Brosnan has everything the other Bond's have. [P2] He is the best Bond
[P1] He tries to emulate the other Bonds, but lacks authenticity, therefore, losing credibility.