After watching this episode through twice, I'm finding it to be a tough ep to grade. I'm largely underwhelmed despite having stupidly high expectations going in... and yet, in retrospect, I'm not entirely sure I expected more from the plot than what we got.
There was a lot of rehashing of the same kinds of jokes from Hungry are the Damned (if they're going to insist on recycling vegetarian gags for Lisa, they could have at least had a bit where they tried to serve her fried shrimp again) and Itchy & Scratchy Land - along with Mirkin's Deep Space Homer homage (that felt more like a do-over of the Two Dozen and One Greyhounds chip gag).
They've got this ridiculous mindset that all of the Rigellians are interchangeable - which resulted in unforgivably sparse usage of Kang & Kodos. Both the voicework and animation direction were uniformly excellent... so once again the execution flaws lie with the writer's room. This episode boasted some weird pacing issues where they literally go 2 minutes from the end of the tour of Rigel VII to decreeing they must eat one of the family - which is a shame because most of the potential this concept offered was the Simpsons interacting with an alien culture on another planet and they literally short-change all of that by fast-tracking the plot and keeping them locked up in a bubble representation of their living room. Like, why would you ever bring The Simpsons somewhere new and then stick them in their living room?
My chief criticism is this - and it applies to what I didn't care for in Simpsorama as well - it's extremely difficult for us as viewers to get invested in the wonder of a concept episode when the Simpson family as a whole behaves cynical and apathetic about their surroundings. When they were captured by aliens the first time in Season 2, when they visited Itchy & Scratchy Land in Season 5, when they visited Australia in Season 6, when they vacationed in Little Pwagmattasquarmsettport in Season 7, when they moved to Cypress Creek in Season 8 - or hell, for a recent example, when they were trapped on the Royalty Valhalla cruise ship in Season 23 - the family was enthusiastic about their new surroundings, there was a clear sense of them being someplace different and we had the chance to get invested in the family being someplace new. Contrast that with this year where they've been a thousand years in the future and whisked to an alien home world and couldn't have been more indifferent about their surroundings. Or, for that matter, indifferent about one of them potentially getting killed/eaten.
No offense to Al Jean but I don't watch this show because I want to see a bunch of cynical fucks. I have these forums for that. I want to see these characters react with a sense of wonder if they're someplace new and you're not giving that to me. Instead you're giving me disinterested Bart, Homer ranting nonsensically, Lisa in the role of plot exposition and Marge is just sort of there off to the side somewhere. You've wasted the future and Rigel VII and had the Simpson family behave like they were at home in both eras. Congratulations.