To be fair as far as my personal opinion goes, external cable routing can be “cool” in light of recent leaps in internal cable routing with one exception. The rear brake cable. We should never have to see this again:
Or far more egregious, this:
I am a fan of both Passoni and Ciocc bikes but the rear brake cable running along the top tube, especially along a beautifully curved compact top tube like the Ciocc above, should see its righteous end now that internal routing has been shown to work. Specialized is also guilty of this on their Secteur and Allez models, as is Trek, Cannondale and to an extent, Giant.
Ladies and gentlemen of all major manufacturers, there is one simple truth about the rear brake cable when it’s run along the top tube (besides the fact that it’s damn ugly): If you hope fans of the sport will ride your bikes hard, and you should, we sweat all over that top tube, and thus, the brake cable. The exposed part of the cable and the zerts that hold the housing ends rot and if not cleaned out regularly (every week or two) they can become so encrusted with sweat you actually have to beat the caps out with a freaking hammer (and a 2 mm Allen wrench). If that wasn’t enough, the cables develop a nice little coating of rust almost immediately, if not sooner. My friends, this simply does not need to be any longer. Please run the rear brake cable inside the frame from now on. We’d much rather just see top tube. Bow-chica-wow-wow.