I've been to Scotch tastings, once with some dude in a kilt from Johnny Walker (I think he was one of the distillers), and they have always insisted you need some water to open the flavors.
If I don't add cubes (I prefer the biggest cubes possible), I'll add a splash of water. 100 proof should get a splash, IMO. For some of the harsher whiskeys (Very Old Barton, for example) some water (or melted cubes) has a dramatic impact.