@halt:
There was no sign of hope for the citizens because they didn't even know what happened. In their eyes the King asked them to trust him blindly but betrayed them at once.
Doffy could've let Riku and the guards suddenly attack the people without collecting the money first but then it would've seemed as if the King had just gone crazy and felt much less like a betrayal and thus the cry for a hero wouldn't have been as strong.
One should also note that Doffy, just as Croc, didn't have many options in overtaking a country but gaining the trust and approval of the population. Both are pirates and Shichibukai so any attack on a country would've alarmed the WG.
I meant hope for King Riku for saving his country….also they DO think he just went crazy, he burned down villages and attacked the citizens out of the blue.
Doflamingo definitely had more options than Croc tho. the simple fact of being able to physically control many at once is a huge plus. Doflamingo was pretty much able to do this in one night (barring research) It took Croc time and many diversion to gain trust, start a civil way and turn them against their king before the war commenced.
the alarming the World Government is another plus Doflamingo has, while i dont know the level of alarm it may give off, i would assume its less than stealing the tributes for the tenryubito and black mailing the Wg; especially if Dressrosa isnt apart of the WG.
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@desa:
I think he contacted the king because he needed him to take all the money and put all the army on the streets so he could manipulate them. By sending them to collect all the money he ensure that everyone would see that they did all on their own free will. Plus the problem of knowing who is in the army and manging to put them all under control at the same time.
i do think he may have did it to get them on the streets for ease of manipulation; thats definitely an option.