IMO, the 3 changeable things that easily make a bike "hot," regardless of age, are color coordination, bar position, and deep section carbon wheels. A lot of the 2000s and 2010s bikes have fairly garish color/graphics schemes. Finding component/accessories that match those schemes, can be difficult IMO.

I posted my circa 2013 Canyon Ultimate on here a couple years back. It received a "hot" however, I think that particular bike is borderline "meh" in real life. The main reason being the wheels are only 38mm deep carbon wheels. When it had deeper wheels, it was unquestionably a good looking bike in my eyes. Even when I do think it's a good looking bike, it's because I'm viewing the bike through the lens of form follows function. It's a climbing bike with virtually no aero considerations, so shallow wheels get a pass. Even at that, the "hotness" difference is made by the color coordination and the fact that the stem is nearly slammed.