Yeah, I can definitely see how having paid DLC right out the gate would've definitely crippled Splatoon's chances, especially considering most of the stuff was in development before the game even came out.
I think the people who got it Day One were faithful fans who trusted that Nintendo would follow through on their promise of the future content being free. And sure enough, that's exactly what they did. And because it was free, and the fact that's there's around double to triple the content there was when the game came out, the people who were waiting to see if they'd follow through before buying the game, bought it now.
And I'm hoping that the way Splatoon was managed will serve as a lesson for future DLC packs for Smash 4 and even Smash 5 on NX, as to how the costumes and stages should be given out.

Outside of the club Nintendo deal with Mewtwo, I haven't gotten any of the DLC. My friend even pre-ordered Splatoon and offered me the DLC costumes, but I wasn't really interested in that either.
I will eventually get all the characters and stages, then perhaps some mii fighter costumes.

That all said, I think the DLC for Smash has been bad. Not the worst or downright terrible, but just bad. It initially didn't seem that bad to me, but the flow of DLC makes the price really pile up. I'm honestly surprised on that end.

I think they have a reason for the continuous DLC and perhaps the price point here and there, but so far its all really speculation on my part so I'll hold off on my conspiracy theories for now

Characters should be $2. Stages should be somewhere around $1. No one really wants the Mii Costumes that badly but they should just be free.

My thoughts exactly

- Characters --- GREAT
Well priced, in line or cheaper with what the industry usually charges from players.
Since the original game already had plenty of content and characters, i have no problem here. Bought all so far and will keep that trend, unless they release something really odd.

- Mii Costumes --- GOOD
My rule for cosmetic is this: as long as it is not shoved in our faces every 10 minutes with advertises, i usually don't care.
Nintendo most likely doesn't expect anyone to buy all of them, just their favorites. If they make a good job, $0.75 is nothing, if they make a crap one, i can just ignore it.

- Stages --- MEDIOCRE
Here is where they dropped the ball, at least with me. It is not unforgivable, but it is well below Nintendo usual DLC pratices (Splatoon, MK8, NSLB) and more in line with the industry average from EA/Ubisoft (though still way better than EA/Ubisoft worst cases).

Both past and new stages feel overpriced, but doesn't fell like a cosmetic thing, they are things that i actually would love to have. Only got the Ryu stage, and won't get another unless there is a stage pack with good price.

- Bonus: Amiibo --- GOOD
Because this will obviously be a thing in this thread eventually, i am taking the liberty of approaching it now.
To the surprise of many i believe, i actually don't care about it. I think it is a weak, replaceable and not very fun use of the amiibos. It is only "good" from a DLC point of view, since it feels almost cosmetic and the game allows you to forget that it is a thing.

It's gross. All of it. I don't give a shit how hard it is to make a party brawler. Four additional characters should absolutely never cost 1/3 of a game that launched with 50. Bullshit.

Bingo.

I'd like to hear your theory sometime or another ;)

But yes, pricing for the DLC is always the issue. $3-5 a piece doesn't seem much until you see how easily it piles up. When wave 5 rolls through, the DLC itself would be worth the same amount as the game itself. Makes me wonder if they will have promos for the other DLC characters..

Too expensive to start with and also why am I paying more for the dlc to work with both the wii u and 3ds. Should be one price for both.
I can't say I like the smash bros dlc practice, especially when hyrule warriors and mario karts were so reasonable.

i miss mario kart DLC scheme.
50% of the content of the game for 12$.
in smash, the 10% cost the double the game price...
I just make it simple: buy DLC like mario kart, dont buy DLCs like smash.
hope developers learn.