House cocktails exist because someone working for the house made a drink that was so delicious it was printed on the menu. Like restaurants, menu items should not be altered to a point where they are no long recognizable.
Should you decide to change a specialty cocktail in a dramatic way, please do not complain about the outcome. At this point, you not liking the drink is your own fault, so keep your opinion to yourself. Stick with the menu as is, or only change base spirits, otherwise, taste cannot be guaranteed.