If you can see how the roster was very big, and how 55 characters divided exclusively to the 3DS version and the Wii U version, it's basically realistic enough to satisfy.
Counting transformations, 55 characters isn't hugely unrealistic, it would take up 51 slots (assuming we don't get any more transformations). However, considering you have IIRC 25 newcomers (made up of many unlikely characters), that's when it starts to get really unrealistic.
The Wii U and 3DS aren't going to have rosters almost completely different than each other.
IF exclusive characters gets implemented (which is a big if), it will almost definitely be limited to a very few on each system (or just on the Wii U), not two rosters with literally no overlapping characters, like you have.
A roster where Mario isn't on the Wii U version of SSB4 can't be considered "realistic" by
any stretch of the word.
How is that? I may have missed a few characters or made some weird character choices, because it was my personal researched roster. So how is 55 characters disappointing.
Because like Curmudgeon said, you'd have to own two systems and two separate games to play as not only both halves of the roster, but the original freaking 8, which is ridiculous. Your roster is effectively for two games with connectivity, not one. In reality, buying either one of your "games" would leave the person with a roster of around 27, with the 3DS one having comparatively few newcomers and the Wii U one not having characters like Mario, Link, Samus, DK, and Kirby, which is... just...
Also, you're not the only one who did research before compiling a roster.
Maybe the newcomers can have much in-depth and more interesting moves to make people satisfied to what they have, like when I was questioning about Olimar's appearance (That's how I became a Pikmin fan). Maybe a friend could help you collect all characters by transferring them, it's pretty likely since SSB is in two versions, and two means twice more sales than Brawl, anyone would be willing to help ya unlock, maybe through even Streetpass.
Sakurai doesn't play favourites, he's not going to purposely make newcomers more in-depth and interesting than veterans, that would wreck the game.
Also, if exclusives are embraced, chances are Nintendo isn't going to let you transfer characters to multiple systems multiple times, that would destroy a huge amount of potential profit. It's not like Pokemon where the characters are a dime a dozen. Chances are you'll link one Wii U to one 3DS and have to transfer solely between them (at least for characters).