Five malts isn't a terribly complicated grain bill. You have a mix of two base malts to attenuate flavor and get in the ballpark for color, you have a little crystal/dextrin for some sweetness and/or body, a specialty malt to accentuate malt character, and a roasted malt for color adjustment or a little wheat for head retention.
Yes you can make good beer with one base malt and a little crystal, I do that with my best bitter. I don't know if it would pass muster at comp level but it works for me. Floor malted Maris Otter brings a lot of flavor, and British crystals have a lot of character.
This is kind of like comparing pot roast to beef bourguignon, they are both good but the fancy dish is generally going to win the competition. Comps aren't the end-all of what is good beer in my opinion. You have to stand out in a comp so there needs to be something in addition to the basics, and thats where the more over-the-top recipes shine.