I'm with you regarding the OS updates, but with the battery, Apple's current service policy is below. If they keep an older version of the Apple Watch around when a new one is released, then they'll be servicing it (i.e. changing dead batteries) for at least 6 years. But on a $5K watch, a 6 year life span still seems questionable? Wonder if they'll change for that the Apple Watch?It won't be any different probably.
Many will not like the fact that their 5000 dollar watch is dead weight either due to battery being dead or because their hardware won't receive the latest OS update.
http://support.apple.com/en-us/HT1752Vintage and obsolete products
Owners of iPad, iPhone, iPod or Mac products may obtain service and parts from Apple or Apple service providers for 5 years after the product is discontinued (or longer where required by law).