Hell - I think it would be hilarious if Wesley and 'The Traveler' showed up together and their relationship was ultimately shown to be VERY akin to that of "Rick And Morty"... [Edited to fix a brain fart of mine - see below ]
I wouldn't mind a Picard cameo. They already have Stewart working on Picard and they can make his voice younger. I also would love some DS9 cameos, like maybe Nicole DeBoar or Armin Shimmerman.
Yeah, I too wouldn't be surprised if that means we'll be seeing folks likes Hana Hatae, Scarlett Pomers or even Wil Wheaton rather than the “big names” like Michael Dorn, Jonathan Frakes etc. But yeah, Patrick Stewart might be a realistic candidate as well, because of the Picard connection. I would imagine just having one of the Kelvin timeline actors as a guest star would make for a neat crossover. I dunno, how about Keenser? The Traveler.
Dwight Shultz has become a kinda rabid right wing talk-radio guy, which makes me think CBS might want to avoid using him.
A time travel episode where the gang goes to the 23rd Century and meet the Enterprise crew and everything is animated in the TAS style. Shatner, Koenig and Takei cameo.
Now this is an awesome idea! This would be such a cool homage to The Animated Series. I also just like the idea of depicting the Lower Decks characters in the style of the Animated Series. Maybe that's something I'll tackle at some point.
Odo's story pretty much ended in the Gamma Quadrant, so he's best not coming back. Nog could easily make an appearance on Deep Space 9 (if they visit), just not a speaking role.
Shimmerman does a lot of voice work nowadays and frankly Quark is the most funny character from DS9. Schultz is still getting work as voice actor nowadays, so that doesn't seemed to harm his voice acting career.
And the Kizinti show up in pink uniforms and Shatner pronounces Orion ("Oh-RYE-on") as ("OR-ee-un"). - Plus Lt. Arex and Lt. M'Ress are there too.
That would be hilarious. Since we got TNG and Voyager characters in Picard, it would be nice to go with DS9 for at least our first appearance of characters from another show. The security chief is a Bajoran, so maybe they go to drop him off at home and stop by DS9. It's only going to be 4 years after the show ended, so most of the characters still there after the finale could still be around.
Also, here’s an opportunity to see more non-humanoids. Maybe we’ll get to see the insectoid Jarada? The Tholian attack on Riker’s dad? The Legarans who were going to swim in that pool or fluorescent goo that Geordi was preparing in “Sarek”? Ensign Vilix’pran from DS9?
Also keep in mind Quark is the only main character who has appeared on TNG, DS9, and VOY. I mean, technically Frakes appeared in all three, but that's only if you count Tom and Will as the same person.
They broke up after their sophomore album when the drummer was caught cheating with the lead singer's girlfriend.