I fear this is still too optimistic, not pessimistic enough. Smash 3DS has shown that past rules of stage representation may not be enough to guarantee a new stage. I still do genuinely fear there may not be a new F-Zero/Earthbound/Kirby stage in the Wii U version. Yoshi, Wario, and Game & Watch are essentially guaranteed, but not sure on the first three I listed.
Though I think Magicant will be shared between the two versions. Mute City I'm less certain on, as it seems more tailored to the 3DS's small resolution. I also don't see F-Zero getting a new stage in both versions when series like Metroid and Donkey Kong can't, so... Not feeling good on a new F-Zero stage for the Wii U version. I certainly
hope the 3DS version's Mute City shows up (
especially over getting no new stage) but... we'll see.
Still waiting on an actual new Kirby stage to feel good on its chances. I wouldn't think Sakurai would skip out on his own series, and as the game already has a major reference to Return to Dreamland, I would like to think a stage from it would be a given, but... well, we'll see.
I don't see R.O.B. getting a new stage. The pattern you detailed for him doesn't really strike me as a genuine pattern and more just coincidence--Fire Emblem's lack of a stage in Melee seems like something they just didn't get around to, not like R.O.B. which can more easily get away with no stage.
The Pilotwings stage could be seen as a "Mii" stage as it's mostly based on Pilotwings: Resort, where you played as your Mii. So I would think it would count like Tomodachi Life counts.
The Wii U version also seems to have more character repped franchises with a stage of their own unlike the 3DS version which has a
lot of holes. It's possible, however, that the new stage count is still comparable to the 3DS version and that the difference came from the multi-repped series. So it's possible there is only one new Zelda stage, for instance, or three Mario stages.
The 3DS version has really re-written the rules for stages if you ask me. Expect even less.
So bare pessimistic minimum, if you ask me, is more like this:
Mario: 3
Zelda/
Pokemon: 3
Donkey Kong/
Metroid: 2
Star Fox,
F-Zero,
Earthbound,
Yoshi,
Wario,
Kirby,
Animal Crossing,
Kid Icarus,
Fire Emblem,
Game & Watch: 7
Punch-Out!!,
Xenoblade,
Duck Hunt,
Wii Fit....
Mii?: 4
R.O.B.: 0
Miscellaneous: 1
Third Parties: 3
Smash Bros.: 2
25, same as 3DS version.