I'll bite.
The device doesn't really need an update. It's a low cost networked streaming device that provides 1080p output on HDMI.
It's low power and perfect to be an 'always on' hub for other household devices. It's perfectly logical for it to take on the Home Automation role since it already has the ability to have a visual interface on a device almost everyone has - i.e the TV. It also doesn't need instructions - it's pretty much plug in and go.
What else does it need to do?
100% agree - the apple tv will be the perfect single hub for different manufactures products. the alternative is to have every company create their own hub which is the current fragmented system. apple tv is almost 100% reliable (the only time i've ever had a glitch is when iTunes is down or i haven't rebooted in months) - its significantly more reliable than my cable companies DVR - Apple not updating it (not counting all the channels they added) i'm my opinion is a good sign that they are doing a complete re-write of the system. I'm very excited to see where this goes.
watch in 2015. I just don't see the watch taking off in the same way. No one's been able to show me a compelling reason outside of the fitness tracker. With the AppleTV, the field is open. They could just do a version of the current one with updated specs and software; they could do one with a router built in, since the network settings are the main pain-point with stuff like Airplay and Remote App; maybe the AppleTV will provide an interface as HomeKit becomes a proper house controller the face for your home becomes your TV.