I am really happy with the Switch, I believe Nintendo has something here. They can dominate both markets with one simple device. All they need to do is put 100% of there focus and games on it. They have the IPs and Studios that Sony and Xbox don't have to push Hybrid devices into market leading territory.
Nintendo can easily create a 3DS successor and it will do well but it also move focus and games away from the Switch basically making the 3DS successor cutting the Switches lunch.