In my mind, there are three possible acceptable ways of designing a connector, in descending order of preference:
Most preferable is a round connector insertable in any orientation. Assuming you’re plugging your headphones into the correct port, you don’t have to rotate or adjust anything: they just work.
Slightly less preferable, but still very acceptable, are reversible connectors. Connecting the MagSafe to your MacBook requires you to ensure that the cable is horizontal, but it doesn’t matter which way is up.
Assuming the rounded connector is impractical for the number of pins and that the pins cannot be reversed, the connector should be shaped to be insertable in only one orientation. A FireWire connector can only be inserted into the port one way.
The existing USB connector is a terrible design, and it has long been overdue for replacement. Unfortunately, the 3.1 Type-C connector isn’t going to be introduced smoothly, as Ars Technica’s Andrew Cunningham explains:
Current USB protocols and connectors are so widespread that it’s difficult to say for sure how long it will take USB Type-C and USB 3.1 to replace them all. Computers with the nearly two-decades-old Type-A plug will be particularly slow to change, meaning that even if phones and tablets are quick to adopt USB Type-C connectors, we’ll still be using adapters to connect them to computers and chargers for some time to come.
At least the ball is rolling. The Type-C connector fits the
third second qualification above so, while not perfect, it’s now an acceptable connector design, in my eyes.
Update: Thanks to Benjamin Esham for pointing out that this reversible connector is, indeed, reversible. I am an idiot.