Where The Orville departs from Roddenberry's vision is its characterization. The lead character played by Seth MacFarlane is reeling from his divorce after having caught his ex-wife cheating on him. Of course, MacFarlane is later forced to command a ship alongside that very ex-wife. This kind of conflict would be deemed too petty for Roddenberry; the revered TV creator would see these futuristic scientists as far too advanced to be absorbed in such "insignificant" interpersonal issues. While MacFarlane looks like a Star Trek captain, he's not exactly written like one.
Meanwhile, Star Trek: Discovery handles conflict in a much more mature way. When Burnham launches the mutiny, it happens because of an intellectual line of thought (justified by her established logical background on Vulcan, mixed with her human, emotional intuition). This nuanced action is definitely more in line with what Roddenberry had in mind for conflict in the distant future. At least, it's an evolution of the conflict Roddenberry established in his original Star Trek. The Orville is a step backwards. However, it's a comedy; it's allowed to be dumb.
Where The Orville's conflicts are mostly interpersonal and only touch on moral complexities, Discovery pushes the boundaries of Star Trek storytelling way further, executing a modern, allegorical take on modern American isolationism and white nationalism through the lens of the Klingons. Discussed at length by CBR's Kevin Melrose, the Klingons are representative of the modern "Make America Great Again!" sentiment that has festered a divisive climate in the United States. Discovery's clever, allegorical handling of this subject matter is an advancement of Roddenberry's science-fiction storytelling, done to great effect. The Orville rehashes or hits the same notes as classic Trek, while Discovery takes it to a whole new level.
Where The Orville chooses to primarily center its story on a straight white male, Discovery has women of color and LGBT characters among its ranks. As The Orville concerns itself with a moderately bickering crew, Discovery has one of its main characters shoot their captain and throw a goddamn mutiny. The Orville is a familiar, safe take on Star Trek that -- regardless of whether you find it funny or not -- serves up age-old tropes that are of course welcome back on the small-screen, but do little to advance Roddenberry's vision for science-fiction. Discovery is truly Roddenberry's Star Trek realized in 2017; The Orville is a blast from the past. They're both fun, but you make take more value from one over the other. It just depends what you prefer from Trek.
The series is currently streaming on CBS All Access in the United States, Crave TV in Canada, and Netflix internationally; it kicked off on September 24, and will run until November 5 before taking a short break until airing its second half in January 2018.
The Orville is set 300 years in the future and follows the exploits of the of the U.S.S. Orville and it’s motley crew, led by the recently-divorced Ed (MacFarlane) who is taking command of a ship for the very first time. Joining MacFarlane’s captain are his ex-wife, Kelly Grayson (Adrianne Palicki from Marvel’s Agents of S.H.I.E.L.D.), his best friend (Scott Grimes), an alien from a single-sex species (Peter Macon), and a gelatinous creature voiced by comedian Norm Macdonald, among others.