I never thought I would say this...but I wish Michael Bay had directed this. Maybe the earlier entries hold something dear to his heart and he wouldn't have allowed this to go off the rails.
The biggest casualty is the riffing between the Lawrence and Smith, which practically rips the soul right out of the franchise. The laughs from the first two movies came from the strong chemistry between the two leads and how they could argue in the middle of gun fights, car chases, etc. Here they just sound like an old married couple who have grown tired of each other.
The other casualty is the action scenes. The great Sam Peckinpah once said of the violence in his films that he wanted the audience to feel the impact of getting shot. Modern day use of CGI and such does the exact opposite. It feels more like you're watching somebody else play a video game. While some praise the visuals, I criticize its effect of pushing the viewer further away rather than drawing them in.
This could have been like Lethal Weapon IV and had some fun with its theme of the loose cannon dealing with aging. Instead its more like Beverly Hills Cop III and becomes a sad entry in an otherwise solid franchise.
