The preference for Orville really shows that many Trek fans are terrified of change and haven't paid much attention to any show that isn't Trek produced after the 1990s. Orville is just TNG with awkwardly inserted jokes. I like it, it's strangely comforting because I also love TNG. But it's a dramedy set in space that appears to use rejected Trek and Sliders scripts as inspiration. Discovery is trying to take Trek in a new direction by focusing more on the characters and developing them, showing them grow. You don't get that from the Orville, it just tells you who these characters are and they don't change much. That's fine, but I like a little meat to my shows and Discovery gives me that. Burnham goes from a mutineer who rejected Starfleet principals in a misguided attempt to protect her captain and ship, losing both in the process to someone willing to mutiny again to defend those same principals from admirals in a desperate attempt to save the Federation. She learned from her mistakes and stopped the war she accidentally started. Tilly went from a cadet with some degree of social anxiety to a trusted and confident member of the crew, even shifting focus to training for command. They aren't static, which is a major improvement for Trek.