Two things. First, I disagree with the scenario laid out in the OP. I shouldn't have to tell my watch that I'm going to bed for my house to react appropriately.
Ideally you should only have to use the Apple Watch for scenarios that you can't already do without one. These mostly involve situations where you aren't home. For example, tell Siri to adjust the thermostat while on your way home.
Ever look into Smart Things or Mi Casa Verde? They both claim to be able to do everything I described today (I've been holding out before trying one). Smart Things even has an open API anyone can build on top of using groovy.While ideal, I think we're still a year or two away from your scenario. iBeacons can tell when you're in certain rooms (Roomie Remote takes advantage of this). I would argue geofencing should tell the thermostat when you're approaching home and IFTTT + Nest does this. Nest is also 'smart' enough to figure out your temp preferences and home/away patterns. To be honest, it's really the only 'home automation' product I own that has actually worked consistently the past several years. Everything else has been riddled with bugs. (*cough* Lockitron *cough* Doorbot, etc.)
I think the commercial office space has done a good job at this. They have motion sensors on light switches with the ability to manually toggle the light on/off. It's simple and it works.
IFTTT falls short really quickly. You can't setup a single rule which says "If this, then these five thats." It can't do simple Boolean logic like "If this and this, then that." You can get into trouble really quickly with nested logic, but I think IFTTT keeps things too simple.Search IFTTT. Most of this is possible now. With IF you can build recipes, if the. Logic. There is already hooks into lights, locks, thermostat, locks and more.
You described now, not the future.
Oh, so it's just another markup language? So, it can be your UI, but then you have a back-end procedural framework do all of the "heavy lifting". We did that back in the day with VoiceXML, creating voice portals. The back end was java frameworks.IFTTT falls short really quickly. You can't setup a single rule which says "If this, then these five thats." It can't do simple Boolean logic like "If this and this, then that." You can get into trouble really quickly with nested logic, but I think IFTTT keeps things too simple.