I'm going to go with Solas. For all his "I am not a monster" business at the end of Trespasser, his crappy plan nearly resulted in Corypheus doing a lot of nasty ****, and it was only through blind luck and a lot of other unpleasantness that things didn't go completely down the toilet. Everything that happened with the Wardens? To the Templars, the Mages and Orlais? All the undead corpses in Crestwood?
The man is a clown, and isn't anywhere near as intelligent or wise as he likes to come off. At least Corypheus had something resembling a plan. Florianne's plan seemed more like an "all or nothing" sort of venture, and Erimond...was an *******.
If he is a clown he wouldn't be capable to survive against 7 Enavuris.
I don't think is fair,since in the end more or less he succeed,he obtained more power and gained the control of the eluvians,tricked the Inquisition.
His fault on Corypheus came out for the fact that he underestimate everyone who is not an ancient elf,still i don't see the strength of your argument since from SOlas perspective even if what he did caused great disasters to many people and brought chaos into the world,he doesn't care so long as it is not his world.
You may be angry at him,but for all the damage that he caused,to the Wardens,templars,the DIvine,the chantry,the mages,the veil ecc..
he doesn't care it is not his world,that's why he is a powerful villain,not a clown..
Also he is an elf not a man.
plus mages,templars,Wardens ecc all of them suffered of indipendent stupidity in DAI,it is not all Solas doing,if FIona was stupid it is not Solas fault,and what about the Wardens? Only 1-2 of them realized that the calling was fake.