If Sony entered the amiibo market, they would need something targeted more at adults. Hard to say how to do that but they'd have to embrace the fact that their audience is simply different than Nintendo's.
I would say just make it a cool way to market DLC. Amiibos that are basically items to put on the shelf that also give DLC. Bloodborne Hunter that comes with Bloodborne items, Galahad with a DLC weapon, Drake with Uncharted 4 multiplayer maps. Stuff like that.