He has a lot of generic and contradicting goals:
1- building the strongest pirate crew: incompetent, weak and pethetic crew with shitty designs and poor portrayal and influence on the arc, tens of thousands of fodder.
-Waiters, giftres, headliners, pleasures: fodder.
-F6, numbers: one shot material.
-Calamities: a trinity of very powerful individuals with zero influence on the arc.
2- die: i guess this is oda's excuse for kaido's lack of aggressiveness, which sucks btw.
3- start a massive war that will destroy the world: he could've started that war whenever he wants, but he's completely relying on doflamingo to do preparation, a war that will start regardless whenever someone finds the one piece.
4- find the one piece: just a stepping stone to start the final war, also a casual goal for all pirates, he also does nothing toward this goal, didn't ask oden or the scabbards about it despite oda telling us that was the reason he killed oden and now targeting the scabbards.
5- build new onigashima/pirate paradise: why would someone who's eager for war hid himself in a natural fortress like wano, also pirate paradise already exists in beehive island.
6- find the ancient weapons: he already has a country of weapon factories, wait... Orotchi made it that way.
7- rule the world: contradicts with 3, you can't rule a wasteland, but looking at wano i guess that's his vision for a decent world, which shows his poor taste.
Other reasons why he sucks:
-He is supposed to be defeated in a matter of hours, keep in mind that he is considered by the world to be the world's strongest creature, when we have canon confirmation that wars between top tiers take days to conclude.
-He fought with big mom for an entire night without a scratch, and now he gets wounded by weaker opponents than him.
-He fell from 10000 meters and just issued a "sigh", and now he is screaming in pain from mere papercuts.
-He is supposed to get his will broken and accept defeat, despite his ridiculous entroduction feats, and what hellish experiences he lived through.
-He is supposed to be defeated in a 1v1 fight.
-He didn't kill the scabbards.