Now that’s good news. It seems the Apple Watch is not a complete deadweight when its battery dies. As TechCrunch has reported, it will be possible to replace an Apple Watch’s battery. The battery is expected to last for 3 years, after which you can get your battery replaced. Who knows how much you will have to pay Apple for that. The good news is you will probably be able to do it yourself (fingers crossed).
As far as CPU and RAM upgrades for premium Apple Watch owners, Apple has not announced any plans. But if someone is paying thousands of dollars for an Apple Watch, they will expect to be able to get upgrades and repair options.