So I quickly put this thing together, I admit my skills force me to do some tinkering ^^
The idea is:
On the MQTT device creation page, there would no longer be the feature search field, but only the button:
When you click the button, a panel would then appear under the button / in a modal / other to be defined, topped with the famous search field, as well as the « catalog » of features, which could be presented like this:
I wasn’t super exhaustive, I admit ^^ but the idea is to see the feature’s « generic » name, how it is rendered on the dashboard, and also the keywords it’s associated with (to decide if it’s really relevant to display them or not).
So someone who starts typing temp will create a filter of all features containing that string, as in the current behavior, but will very quickly see what they’re looking for: a temperature sensor? A dimmer? A color temperature dimmer? a storm detector?! 
That’s the overall idea. Thoughts?