Smash has crap tons of DLC, there is no doubt. Although it's not that different from TLOU and similar. The great part of both of these is that none of the DLC is required for either. If you don't like the DLC, don't get it.
I don't really like all the DLC, but at the same time nobody is forcing me to buy it. I have purchased a couple bundles of DLC for Smash, they total about 12-15 bucks I think, they came with some new characters and stages. I don't think that's out of control at all. There are costumes for Mii's for those that want it, but again nothing is forcing anyone to get it.
The opposite side of a game like Smash with DLC is Splatoon. All the DLC is free so far. Fantastic. The content was a bit anemic before, but other games have been released with similar but have charged for the DLC or expansions to make the games full.
Amiibo as DLC aren't good IMO, but I do like them for the collection purposes. I'm not a full collector or anything like that, I just get the ones I like.