I don't have a horse in this race, but being able to specify a generic target and then having a documented manifest format sounds nice to me?
Then you'd be able to do the ol' "specify base url" and as long as that host answers appropriately it should Just Work ( also doesn't stop you from then having npm configured as the default ); source freedom without blowing up configuration complexity
Publishing on the other hand I don't have easy recs for that don't eventually result in a lot of special-casing; That said, npm, git-compatible, s3-compatible, and ftp-compatible would cover most use cases, I think? Beyond those deployment types, custom deployment needs may well be better suited to pay you for a support contract anyway? )