There were probably a lot of people that heard this idea the first time and thought that it made little to no sense considering that the MCU and Star Wars universes are so extremely different that of course there wasn’t bound to be a Luke Skywalker cameo in the new show What If?. It sounds as though this was something that Kevin Feige was quick to shut down without hesitation since a Marvel/Star Wars crossover is something that many people still think should happen, but it’s not going to take place just yet. This makes sense on a couple of levels, one being that it’s better to take stories that have already been established when it comes to a program like What If? in order to flesh them out in a different direction while retaining a strong base to work from. There’s no strong base between Marvel and Star Wars at this time, and to be fair, it’s hard to see how one could possibly be developed since they’re two very different universes. Where the MCU is filled with super-powered individuals throughout the galaxy, Star Wars is a little more specialized than this.
The second thing that makes sense is that crossing the two over would require a very carefully monitored story that might not work for everyone but would be intriguing to see at the least. One has to wonder a Jedi or a Sith could exist in the MCU and still access the Force, and whether it would be a weaker connection or a stronger one. When thinking about it, the energies that run rampant in the MCU might actually be another version of the Force, since when thinking of this from the other angle it might mean that the Star Wars universe has a good number of super-powered individuals that all draw from the same source in one way or another. A crossover between the two feels like it would become complicated very quickly, and would be heavily criticized by the fans.
On top of that, why bother? Is there really such a great need to slam everything into the same mashup? There are definitely times when combining stories could be kind of fun, but those moments are usually fleeting and don’t need to become the norm as some people would like. Lumping everything into the same story though would be a pretty big mistake since keeping every story as it is in a unique way is usually the best way to please fans since there’s something for everyone and a variety for those that like to enjoy each story as it is. It’s definitely possible to bring such an idea to bear, but the time and care it would take needs to be recognized. A limited series dealing with the multiverse and the two different universes might be a possibility, but otherwise, the two need to stay separate since there’s been nothing established between them as of yet, at least not in a significant way. Seeing a Luke Skywalker cameo in the MCU would be kind of odd, to say the least, which is a good reason why it’s not going to happen.
So far it would appear that the What If? series will be looking into the stories that have already been established, meaning that it will be going through the movies and possibly inviting a bit of added thought to what might have happened had things gone just a little differently. One can only hope that Endgame is involved since it would be great to see what else could have happened in order to stop Thanos. Of course, so much is bound to change on the way to that moment, if it happens, that one might not even fully recognize the team by the time all is said and done. To think that such a small movement or moment could be enough to alter the course of history is mind-boggling, but upon really thinking about it the chances that a lot could change from such a small moment becomes feasible since it takes so little to upset the balance of any system. As of right now, it’s been established that Captain Carter has taken over for Captain America, so it’s fair to say that whatever comes next will be just as big of a surprise.
If an MCU/Star Wars crossover ever does happen it might be something that will be akin to the near-disaster in the comics that saw DC and Marvel going at it, but until that happens one can rest assured that we won’t be seeing a cameo from any Star Wars character in What If? simply because nothing has been done yet, and probably won’t for a very long while if Feige has something to say about it. For now, What If? is just fine as it is.