Yeah, it totally works, but you can mix an amaro with sweet vermouth and anything and it will taste good. I almost always make my Negroni with equal parts, but don't make that mistake with the Boulevardier. I go 2:1:1 or 3:2:2 bourbon:vermouth:amaro.
For something a little more obscure, try the Cocktail a la Louisiane, one of my favorite whiskey cocktails:
3/4 oz. rye whiskey (I use Sazerac or Rittenhouse)
3/4 oz. Benedictine
3/4 oz. sweet vermouth (Carpano Antica recommended)
3 dashes absinthe (sub Herbsaint)
3 dashes Peychaud’s bitters
Stirred, strained of course. Garnish with a Luxardo cherry. Delicious.