Doflamingo's reaction speed took a heavy deep ever since gamma knife to the point even base Luffy could outmaneuver him at one point when he seemed untouchable before even by gear2 Luffy. He is still fast, but not as before. Gear4 then came to overcome the difference in speed with a power-boost to boot. Eventhen, he could still outmaneuver gear4 Luffy once(his calverin move) kicking him on the side only to be surprised he is still made of rubber, still analyzing Luffy's moves and how his mode works.
Later on, Doflamingo realized there is a timelimit in the gear4 mode, and started to outlast him(which is a less risky method especially in his current state), and during 20 minutes worth of time, Luffy couldn't land hits on Doflamingo(who was forced in a defensive position where he had to dodge his awakened attacks instead) despite the fact Luffy was heavily pressed by the gear4 timelimit, with Doflamingo blocking a double calverin with threads forcing Luffy to brute force through it and land his leo bazooka attack(his strongest one hit attack in the mode), and attack that very likely wouldn't finish Doflamingo when the gear4 timelimit will inevitably kick in
If even during gear4, Luffy can't do much damage to a weakened Doflamingo with consecutive attacks, including his strongest one hit move(with Doflamingo continuing to come back without slowing down) despite being pressed by time, i'm not sure if i would really call it a punching bag fight. Though i guess the result will depend on following chapter