MCU: 10 Things You Learn Rewatching Thor
1. Loki Has The Same Problems As Other Marvel Villains
It's long been posited that Marvel has a "villain problem". It's easy to see why that narrative took hold, too; unlike other superhero franchises like Nolan's Batman trilogy, Marvel's focus has always been on the heroes, and in building them so well the villains have mostly fallen by the wayside. Phase 2 perhaps fared the worst, with Whiplash and, uhm, that guy from Thor 2, being some of the most one-note and forgettable baddies in the entire genre, never mind this universe.
Thor's Loki has always been said to have avoided the same pitfalls that consumed those other villains though, and while that's true, the reasoning could simply be because he's been kept around the longest, and thus has had more opportunity for character development.
If he got the straight one-and-done treatment as everyone else in Phase 1, looking back, he probably wouldn't be as revered as he is. He still has more depth than other Marvel big bads, with his winding conspiracies and sibling rivalry with Thor giving him a distinct personality, but that's undone when he goes from being a bit of mischievous dick to murderous psychopath in the space of about 5 minutes of screen time.
His thoughts of betrayal and his family issues all provide great drama, but the character loses any sense of relatability with audience when he suddenly becomes yet another blank-slate punching bag.