Guess I should share some insights to the reviews I make:
So, I measure a villain by a four-part criteria: Biography; Personality; Appearance; and Abilities/Powers. I rate each one out of ten and then add them up and divide them to get the final score. As such, it tends to be unlikely for a villain to get a perfect 10/10, but they also won't be so bad that they fail each part of the criteria. Again, a lower ranked villain does not mean that the villain is terrible or badly written, but in terms of entertainment, I find them less appealing IMO. It could come down to personal tastes or the core of their villainy.
Pretty obvious. The villain should at least have a substantial backstory. Now, this is not to say that all villains should have an overly complex backstory, but at the same time, there should be at least a sliver of explanation as to why they had become the way they are. Villains like the Joker, Anton Chigurh and the like have backstories that are near to impossible to fully know or understand, but that is not an issue because ultimately, the characters were molded by whatever happened to them and their crimes do lean towards an inferrence. But if there is a villain that lacks a backstory and they are really given no motivation behind their acts aside from being evil, they are likely to score lower in that field.
Again, to me what makes a good villain is the fact that they are entertaining in some way. Some villains can have funny sides to them like Bill Cipher or Aku. Some can be charismatic and orchestrate events flawlessly thus leaving the viewers at awe with their brilliance. Still others can be truly sympathetic figures that have become the way they are because of great tragedies. Slightly more complicated is the typical purely evil bad guy with no redeeming traits. It is complicated because with their main gimmick of being an evil, vile, monstrous character, it can come off as boring because that would make them relatively flat and character development is unlikely because that would come at the risk of giving them traits that might give them redeeming factors. In some instances, I think it can work.
So a villain can be anything: wickedly smart; goofy; short-tempered, etc. They don't have to be completely complex, but that is not to say that well-written villains are automatically disqualified. But there lies the Generic Doomsday Villain where the villain is not so much a character but more an obstacle given sentience. They have no clear goals or motivations and lack a personality. They are literally there just to be opposing the heroes. A GDV is different from a villain that commits For the Evulz because at the least that does serve as a motivation behind some villains' actions as they practically live to be as dark as possible (like Johan Liebert or The Lich). Even characters that don't speak like Michael Myers, Jason Voorhees, or Art the Clown have personalities and often make body movements that suggest their current mood.
Simply put it lists some of the villains' defining powers and traits but also their weaknesses. The villain being reviewed doesn't necessarily have to possess superhuman powers as their intelligence and manipulation/charisma is also considered.