I have to guess it was Namco who came up with the DLC model because it essentially follows the DLC model for other fighting games.

The fighter bundle includes the 4 DLC characters that have been out plus Ryu's stage. I don't think Mewtwo is in Collection 2.

what if someoen only has a wiiu they would eb paying the same price as somebody else for both versions when thye wanna buy 1 version.

It's not bad. It's terrible.
I fear for future Nintendo franchises.
Green tunic, red tunic or purple tunic for 3.99
White Epona for 2.99
Biggoron's Sword for 2.99
etc.

Fighter bundle includes all DLC characters including Mewtwo.. which means you get Roy, Lucas, Mewtwo and Ryu + Suzaku Castle

This pack does not give any discount compared to purchasing each DLC character separately, but instead allows for easier shopping on eShop as buying multiple DLC is rather confusing

I don't see the problem, it's the same as cross buy on the Vita. Nobody cared or complained that they were paying for a vita copy of a game they couldn't use.

My 3ds copy of smash is now even more inferior because to get both its even more overinflated than the standard price already is.  

The kicker is that if I now decide to buy the dlc for the 3ds, I have to pay full price again as I can't upgrade my already purchased dlc. 

I doubt it will get to this degree, but Nintendo can definitely make even worse DLC options. They have already included Day 1 DLC, but I don't see them charging like this. The closest I can see is with locked useful or good weapons with Amiibos (like in Splatoon) :/

No, the price is the same. If you purchase all the DLC characters plus Suzaku Castle separately, it is exactly the same price as the Fighter Bundle

The reason it's even there is to allow people to buy them all without needing to purchase each one by one

Yes, when you buy this pack, you get all the current DLC characters only

No stages are included, with the exception being Suzaku Castle (as it's bundled with Ryu)

Not a big fan of the pricing model, though I do like how I can pick and choose what I want. There's a ridonk amount of Mii costume DLC that I have no interest in...and thankfully I'm not forced to overpay for packs that throw them in along with content I do want. Other than the Street Fighter stage, I don't think I really cared for any stages, so I didn't feel forced to buy them either. That basically just left me with Roy and Ryu for both games, which wasn't a huge added cost.

Still...I think this game would have benefited from a Season Pass or a more appropriately priced DLC package. I was really impressed with the amount of content included in the DLC packages for Mario Kart and Hyrule Warriors, so it seems like Nintendo sorta took a step back with this game.