Your app idea is a method I have used in the past. I started a note in Evernote and when I tried a new bottle of wine, I would take a picture of the bottle, write a comment of it's quality [Avoid, Okay, Pretty Good, Fantastic], write down it's basic characteristics, and then write what food I thought it would pair well with.

One thing I have noticed about wine though is that even with a bottle of wine that I really like, the next bottle I get of the same vintage might be terrible. What the article does not mention is how important environmental conditions are for storing wine and how a case of wine can sometimes get ruined in shipping, sitting on a store shelf or not allowed to breathe properly.

Because of the amount of variation in wine quality I have adopted the habit of just buying $6 - $15 bottles and when I find something I like, I stick with it until I stop liking it. If it's a special occasion, I will put my faith in a nicer brand that I have tried and liked before that I believe will pair well with whatever food is being served but for the most part, buying expensive wines is too much of a gamble for me. Especially considering that my wine palate is not much more complex than your 3-star system.