I think it's a bad idea unless it only applied to hardcore mode
or if it were to affect the lower difficulty modes then they should only "burn out" when water or rain touches them
so if you shielded your torches from water in the form of say a jack o lantern, or inside a house with a ceiling 2 blocks thick
nothing should happen to the torches.
I can see why people would want a more realistic mechanic for torches and it would make the other lighting sources more valuable/useful.
But at the same time it would become an incredible annoyance to have to keep replacing torches in the town you've spend so many weeks constructing just to protect it from Creepers. Someone told me that people can just play in creative mode, which I respectfully disagreed with him on.
I don't believe somebody should be forced to play on peaceful or creative mode just to exercise some creativity on the worlds they play on.
and Mojang have obviously thought this issue through, otherwise torches burning out in the game would already be a thing by now.
This was a feature that was introduced--and then immediately removed (I'm not sure if players ever saw it in action)--in I believe one of the 1.8 snapshots. It was deemed as not fitting into the vision of Minecraft as a simplified sandbox.