The concept of bruising gin is equal parts truth, and wank. Truth in that it does somewhat alter if not the taste per se, then at least how it rests on the palate. Wank because really, of all the words we could use to describe this effect... aerating, berating, incloudulating... 'bruising' seems to be the tossiest.
Source: my knowledge of all things wank, wank-like, wankesque, and wank-foolery, as evidenced by my use of the terms 'per se', 'palate', 'as evidenced', and 'thirst world' (wait a sec)... and my willingness to invent whole new words and phrases to illustrate a largely irrelevant and completely first-world (or thirst-world - BAM!) point.
There are certain cocktail which I feel benefit from a severely 'bruised' gin. A Last Word, for example, or indeed any of the so-called 'corpse revivers'. Those drinks I like cloudy, sharp, and punchy. A Martini, on the other hand, should be made thus:
Chilled to within an inch of sanity, by way of pre-chilling the gin (only necessary in hotter climes), pre-icing the class AND garnish, and of course stirring with ice. The resultant beverage should be so crystal (from lack of shaking and more importantly from lack of Vermouth), that one can clearly see through it - to the bartender - who is dutifully making your second round. And YOU, dear sir, should tip that bastard generously. He has a beard to feed.