>the first arch-enemy
>predated Scarecrow's fear toxin and even back in the 1940s used it for a far more ambitious goal than Crane usually does
>is in peak physical shape, oldest appearences have him be bigger than Batman and most others have him be able to impersonate him flawlessly
>arguably just as insane as any other Batman villain but consistently maintains good public image, which all the others fail at
>hardly sacrifices competence for personality or humor, which is a balance Batman writers still struggle with to this day
>criminal mastermind that actually earns the fucking title unlike a good majority of the other Batman villains
>perfected the art of systematically ruining Batman's life and digging into his psyche long before it became a cliche to have new villains do so
>exploited his knowledge of Batman's identity in ways other villains wouldn't dare or go that far into
>henchmen range from standard mobsters and criminals who he actually leads with charisma, to specialized allies and agents (Sanjay from Monster Men for example), to genetic monstrosities, to actual Kaijus
>has actual weaknesses, neuroses, humiliating moments and so on that prevent him from becoming a Villain Sue and make him a far more dynamic character
>started out as an amusing but standard pulp villain, and after a 3 decade hiatus, developed into one of the most cerebral, obsessive, interesting and dangerous Batman villains of all time
>did all of this without so much as a tragic backstory which the majority of Batman's rogues rely on, his personality and competence were enough
>had a continuous development, with each appearence being built up from the last, an absolute rarity in comic book villains (this didn't last into the 2000s sadly)
>barely over 20 actual appearences and yet two of which are held up up as among the greatest Batman sagas ever written (Strange Apparitions and Prey), several others being the best or among the best of several writers's work on Batman (Gerry Conway, Matt Wagner, Steve Englehart, Doug Moench, Tom King, Devin Grayson), and the worst stories he has are ones that don't even really involve him in the first place.
Honestly, by all means, Hugo Strange should have been the unarguable greatest Batman villain of all time. It's such a shame that few actually paid attention to him until Arkham City built up marvelously only to make him a sniveling patsy to Ra's, both overshadowed by the Joker, and that nowadays he seems to be treated as the standard mad scientist he's long grown out of.
Although in a way I'm glad he's remained very under the radar and wasn't ruined by overexposure like the Joker.