Re: If the Guauntlet fits, you must admit .... it's time for Thanos!
I think villains like memorable villains. Memorable does not necessarily equal layered. Take, for example, Jack Nicholson's Joker. He wasn't a layered, nuanced character, but the general public loved the character. If you think that a villain needs to be layered to be memorable, may I direct you to Star Wars. Three of its most popular villains, the Emperor, Boba Fett, and Darth Maul, are all straight up bad guys without any sympathetic history or back story presented in the films, nor are they ever shown to even be capable of doing good...but people love them because they're evil and badass. They leave an impact.
Thanos does not need to be sympathetic. Just awe inspiring.