If you ask the average Marvel fan what they think of Phase 4, they’ll probably tell you about their gripes with the over-saturated scene of mediocre movies and TV shows. But amidst the flood of underwhelming content, “Loki” remains as a shining example for what Marvel Studios can do when they’re at their best. Loki has always been a beloved character, but the closest we ever got to diving into his deeper motives and personality was in “Thor: Ragnarök.” He died in the opening sequence of...