Still, Rosalina got in after being playable in 3DW. Also, Jr. was hated by the fans for replacing the Koopalings circa Brawl. It would take NSMBW to mitigate the opposition to Jr.
The fact that they were planning, through things like 3D World, to keep Rosalina relevant beyond the Galaxy saga definitely helped her get in. But they still added her at the earliest possible opportunity. They did not do any waiting or seeing, and the character generally had really good timing that helped her get in.
I remember Jr. being a largely popular request for Smash. I do remember some hate for him but it was not really any different than what any other popular request gets.
They waited with Jr., yeah, but that's just one character that I do not think Sakurai values as highly given his history of lower priority.
but Lucario and Incineroar were too?
The specific choice of Incineroar itself was apparently decided after Ultra Sun and Moon released, but a slot was held open for a PKMN, and it's pretty safe to assume this slot was for a recent PKMN or else there would be no reason to wait (this is per a Sakurai interview).
Lucario I may have to correct myself on as I cannot find a source for when he was decided. It seems likely that it was a similar situation to Greninja/Incineroar, though, given that history.
They are all still pretty blatantly "recent game advertising" picks added very early in their respective histories, however, which is what the actual argument was about.
Honestly, Zelda games after the "Wild Saga" seem poised to continue to be just as special. The Zelda team clearly doesn't feel obligated to repeat the "two buttons to assign items" system or the "two acts of dungeons" structure, so they're not going to feel obligated to maintain everything BotW brought.
The series simply weakened after Majora's Mask and fell into a full-on slump with Twilight Princess lasting until Skyward Sword, partly due to technical limitations introducing difficulties making and filling up explorable worlds, and partly because they tried to chase the conventional storytelling that was popular circa the PS3/360/Wii gen despite it objectively gelling poorly with the video game medium. Also, the Zelda team clearly has no talent at conventional storytelling.
The Wild Saga won't be another peak, mark my words. It will be a stepping stone for just as great or greater things.
BotW (just the first one on its own) is widely considered one of the best and most influential games of all time, with sales to back it up as well. On that basis I think a BotW-exclusive rep is justifiable, even outside of Link being stylized after BotW (which I oppose in favor of classic Link anyway). It has nothing to do with how the series might go from here on but rather has to do with the legacy established already.
I don't see how TP and SS were a "slump." The sales are in line with the rest of the series and the critical receptions were very good from basically all major outlets. They are not perfect games and you might have personal problems with them, but they were very high-quality games.
Don't underestimate the importance of being a numerous threat and dying en masse. Would you argue that Stormtroopers in Star Wars aren't iconic?
"Numerous threat" does not amount to importance, especially when there are many such mooks and no such species individually has a specific role beyond being a minor recurring obstacle.
To the question: no, but despite being recognizable or iconic, the Stormtroopers do not qualify as "allstars" by any stretch of the imagination.
I keep saying this, but Impa is simply too inconsistent to provide a good idea of how she could fight. Giving her pretty much anything, made up or based in canon, is asking for a Ganondorf/Wario situation.
I don't think that's a reason to exclude the character altogether. I don't think hardly anyone wants Ganon/Ganondorf or Wario removed altogether, at least not these days with a 50+ character roster.
I'd always been in favor of having BotW Link as the base Link while the old TP and/or OoT Link is classed as an echo.
My bigger priority with Link is just having one of them. I'd willingly take the current alt costume setup over basically anything more elaborate, and really the current setup isn't bad despite the left-/right-handedness issue (even Skyward Sword has the right-handedness anyway). I just vastly prefer the classic look and would like that at least as the default.