Fermented sauces defiantly have a flavor characteristic unto themselves that some people like and some don't. To me fermenting enhances the flavors of the ingredients without really changing them. I mean a fermented pepper mash to me still has that fresh pepper flavor but a bit more mellowed and I like way the lactic acid enacts with it. I've never noted that the flavor of vegetables, peppers, onion, garlic, etc has ever been changed but I agree that fruits are changed through the fermenting process. Some fruits are better for fermenting than others, for instance I wont ferment a lot of tropical fruits for instance mango, papaya and pineapple just don't do well in a ferment. While a lot of other fruits, most all berries, apples, pears, oranges and such do really well as do raisins. If I want to add some tropical flavors to to a fermented sauce I'll add them during the processing so that their flavors stay true and generally I want their sweetness added to the sauce.