"Cognac is an acquired taste" is BS. Cognac is no more an acquired taste than any other spirit, especially compared to peated Scotch. Bourbon doesn't get classified that way because it's an American thing, and we are used to it. Remy XO is where that brand starts getting good though, and
rancio begins to express in a pronounced way. Fractional blending is the norm in Cognac, and I hope it stays that way. I have had many vintage Cognacs and they are never as good as the blends. Interesting, yes, but never as good. Armagnac, too, and Calvados. Blending makes it better.
And yeah, spirits do not go bad. Sponge, when you open it, give it a little shake before pouring. The top layer will have evaporated a tad and shaking it will mix that in so you get a better representation of the spirit.