Each varietal of grape has it's own unique characteristics-including body, flavor, aroma and color. A Cabernet may be described as rich fruit forward with blackcurrent and cherry flavors...full bodied and heavily oaked. A Pinot Noir, on the other hand, may be described as rich, silky and smooth with notes of toast and raspberry...light or medium bodied with a medium oak intensity. Tasting these two wines next to each other...you can certainly tell them apart
There are many wines made from a blend of 2, 3 or more grapes. These blends sometimes bring out "The Best of Both Worlds!" You may not care for a Shiraz by itself, but blend that Shiraz with a Cabernet and you have a harmonious mixture of flavors from both grapes. There are times that one grape or the other will be dominant, but I notice through the aging process they will transform and different charateristics will emerge from the wine.
Aging red wine can certainly be beneficial. The "bigger" a wine is the more it will benefit. By aging, the wines will evolve with more complexity and flavor. The strong fruit flavor of a young wine will mellow into a drier finish. The harshness will soften to a smoothness.
Thank you for listening to my ramblings! I love all types and styles of wine, each one being unique in it's own way. I like to suggest that you venture out of your comfort zone and try some wines that you normally wouldn't drink. So many wines...So little time!