12GB RAM does seem high but one area Nintendo doesn't skimp traditionally is memory. And as said a good chunk of that may go to OS/backend/recording, as right now Switch only offers a paltry 750MB for that.
Looking at it compared previous revisions:
GB: 8kB + 8kB video -> GBC: 32kB + 16kB video
DS: 4MB -> DSi: 16MB
3DS: 128MB -> n3DS: 256MB
NSW: 4GB -> NSW+: 12GB?
Looking at it compared previous revisions:
GB: 8kB + 8kB video -> GBC: 32kB + 16kB video
DS: 4MB -> DSi: 16MB
3DS: 128MB -> n3DS: 256MB
NSW: 4GB -> NSW+: 12GB?