Dressrosa is a trigger of a very important future event, where Luffy gained important allies that would probably help him during a final war arc similar to Whitebeard pirates and their ally but thousand times more powerful and impactful, hence why Oda decided to develop them a lot during this arc and it couldn't have been possible if the entire strawhat pirates were there when you see that even for the present ones, they lacked a lot of screen time with the involvment of Law, his backstory, fbs and inner arc important characters development around Kyros, Rebecca and the lot not helping either.
Because of this, this arc felt boring at times with horrible pacing and it comes out as even worse when you think about the inactivity of some early introduced important characters like Fujitora, CP0, Burgess and others like that whose presence is so minimal that you can even forget they exist(just like with Manshelly). But this is just pacing problem, so maybe if you read the arc at once, you could enjoy it more. The main problem however is like you said concerning the fights. I honestly didn't feel any of them besides the Franky vs Senor Pink, who ironically seemed to be the best fight in dressrosa to me, yes even better than the Luffy vs Doflamingo where not only they were fighting by sequence(always interrupted) but where no real tension exist. At this point, i even consider the Luffy vs Chinjao as a more enjoyable fight
This arc was good though because of the introduction of new good characters with their perspective in future events(like mentioned earlier) with guys like Bartolomeo, Cavendish, Sai and his gang, Ideo who were really enjoyable. The bad plot and fake tension alongside horrible pacing is ruining everything though and the worse thing is i feel this arc could still be dragged until chapter 800 knowing Oda. I can't wait for this arc to finally end. Dressrosa may be good, but it's becoming too much now and boring