Well, you could argue Find Mii did that as well with the creation of the royal family.
And is giving them "depth" really justification for basing their Smash incarnations entirely around that? After all, Miis are ultimately player avatars, so why not incorporate the wide variety of roles they've allowed players to place themselves in?
...Not really. Unless you're also going to say the
other non-Puzzle Swap Streetpass games do too....
All the Streetpass games do are have the player's Mii fill a role designed on the game. Introducing the Prince and Princess in Find Mii II isn't giving depth to the Miis; it's only creating two defined characters to serve a specific role (like Mr. Mendel, Wentworth, Iris, etc.) much like Blue Toad and Yellow Toad in the NSMB titles (do
they provide depth to the Toad race?).
Tomodachi Collection, on the other hand, allows the Miis to be fleshed out, given personalities, be actual characters and not just a generic avatar or filler for a pre-defined role.
As for your last set of questions, they don't make any sense.
If you're talking about in terms of moveset, no one said anything about having a moveset strictly based on the franchise. Though it's possible, a more likely assumption would be for Miis to have a collective moveset. Doesn't mean they can't be primarily Tomodachi style like how Wario is primarily WarioWare style despite having aspects of
both of his series.
If you're talking about
design, then you're literally saying we should have this:
instead of
this:
Which makes little sense.
