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Better manufacturing could be an internal revision of the current model utilising a better fabrication process. Also the current model has a daughterboard for the 32GB flash memory I believe so a 64GB revision could easily be introduced without revising the main board. Not forgetting colour variations and special editions of the current model too. I don't think we will get through this year without some of this happening. Maybe I'm wrong but I've a feeling in the past they have announced new revisions with short notice too so as not to affect existing stock selling. I would think September is a likely time to announce something for the Christmas season with the revision available shortly afterwards.
However sometimes commercial factors are the catalyst. If Switch sales start to slow or Nintendo can manufacture a revision at a reduced price compared to the current model then their motivation may increase to release something new.
