Originally Posted by blalex620
The GA audience can be very fickle. People loved Loki because they felt bad for him in the beginning and the actor did a phenomenal job portraying him. People loved the Joker because of the sheer audacity of his actions and once again a phenomenal portrayal by the actor. Have the right actor portraying him and an excellent story pertaining him and the audience will eat him up.
I love Thanos, obviously, but movie audiences tend to love villains who are layered and complex instead of one-dimensional. Loki and Magneto and The Joker -- especially Ledger's version -- are very multifaceted and fascinating; one-noters like Red Skull, Abomination, Whiplash, Parallax, Ironmonger, and Topher's Venom far less so.
It'd be hard to add layers beyond "megalomania to the nth extreme" to a character like Thanos.