OKAY, for one Pokemon and Smash are different. A fighting game is nothing without its characters. You can have all the neat and intricate mechanics and systems you want, but without a varied cast of characters to make use of them in different ways, it means nothing. So yes, having a fighting game is incomplete when some of its cast are excluded. It's not exclusion. They are merely different games.
Unless of course, the 3ds version has no exclusive content. Then it would be exclusion.
The whole idea only came about because one (very pessimistic, I might add) guy thought the 3DS JUST COULDN'T POSSIBLY have a large roster of characters. He was also convinced the 3DS version was going to do terribly because I mean it's on the 3DS y'know. Awful. So "not enough space" and "more sales," the one I'm guessing you subscribe to, are the two primary reasons people expect exclusive rosters.
So Smash 3DS needs a separate cast to make sales, huh? Why? Does a SMASH game really have to worry about sales? Is freaking Starfy or Isaac going to add sales to it? The only CHARACTERS that could drive sales are like, the original starting eight? No one's going to buy another Smash game just to play as MUDDY MOLE or something. What do you think having no reason to buy the 3ds version will do to sales?
People also think these characters would be transferable, not understanding what that entails. For the characters to be transferable, that would require ALL THEIR COMPLETE CHARACTER DATA on BOTH VERSIONS. So that kind of destroys the "not enough space" argument itself. So basically, transferring characters only acts as a "key" to unlock already existing characters. Sakurai, for one, probably wouldn't believe in this kind of marketing scheme. I couldn't point to any sources, but he seems like a man that likes to make a game as complete as can be the first time around. Nintendo also apparently seems to have learned that people hate DLC that works like that. They say over and over again that DLC will be additional content that's worth the money. That is not QUITE the same as this situation, but it shows they would probably disapprove of it as well.Additional characters and stages woudn't be worth the money? maybe if they were $10 each, but Nintendo wouldn't do that, for exactly the reasons you detailed. They'd likely charge, $1 or $2 Besides, If you had the 3ds version, downloading the exclusives would be free. Keep in mind, what I'm suggesting is not on disc. It is a download. Plus, the DLC could increase Replay value, when Nintendo releases even more content after the games released. Off disc DLC on the 3ds has already happened in the Mario kart 7 online patch. It's confirmed for 2 future 3ds games. And there is a problem if the Wii U can't do most of the processing type stuff the 3ds can.
Let's see, what else. It only increases the amount of work load for less gain. They would have to work even harder to create all those extra characters that don't appear on each version. I can't really form this other idea into a sentence very well... BUT LIKE. Sakurai isn't going to sit there and consider which characters would be better on one version over the other. He's going to consider what characters are GOOD. Characters that ADD something to the game are best for both versions. A lot of people see exclusive rosters as a way to include more characters as a way to avoid saying "Toad should get in over Bowser Jr." or something. But if Junior isn't worth then he just plain shouldn't be in Smash. That accommodation bull**** is for the WEAK. I don't follow what you're trying to say here.
Also, stop saying "Nintendo will do it just to make money." It's a bad decision because it will make a lot of players feel cheated out. If they can't play as one character on one version because it's in the other version, that's going to cause a lot of BUTTHURT. This also doesn't effect Pokemon, because it's so easy to trade and stuff now. That's also kind of one of the founding pillars of Pokemon. BUT ANYWAY THE POINT IS, that kind of DISSATISFACTION is what would cause Nintendo to lose money. It is the only way they really could make money. They wouldn't be being greedy, they would be being good businessmen. It would be an unfortunate necessity.