Change the text-based entry for “Location” into user pre-defined “Locations” (e.g. in Settings) and then subsequently Device locations are assigned via a drop-down in their individual Device pages.
Would be useful for trends and historical data.
Some sort of “known” locations seems a good feature request. How it’s implemented is up to you guys.
Instead of drop down, you could implement which suggest would do the same without the drop down (which needs edit etc.)… If I type location “kitchen” once, then next time I type “k” it gives me “kitchen” as suggestion.
One challenge here is that some (many?) people use “location” as one field to put random other stuff in 
Having more meta data per devices is probably gating location specific development.
I also thought it would be handy to have a user created map that they could pin “bubbles” or icons to. It would be mostly a background thing so maybe not to app development intensive but would give the user a very easy to read picture of what is going on at your house. You really wouldn’t even need to have labels, a location and on/off icon would give you all the information you need, though having the wattage in there would be nice.