How many other plugs are reversible? HDMI and DisplayPort aren't. Older stuff like scsi, gameports, parallel and serial ports and the like weren't, and could even destroy your hardware if plugged into the wrong thing. Firewire and GameboyLink weren't. Barrel plugs are insertable every way you want, but only have two contacts. And 3.5mm jacks slide over all the pins, which might not be great if you plan on carrying power.
Lightning and USB Type-C are reversible, but that's the only one I can think of. And the inoffiziell rarely seen reversible USB Type-A (when were those first released?).
Biggest problem with USB Type-A is that it isn't keyed in an obvious way, so both directions of insertions look and feel plausible until the thing doesn't wanna fit.
PS: Another thing "wrong" with USB is that Type-B isn't a female Type-A, but a completely different thing, meaning a USB cable can't be used as extension cord and you need a different cord for that. As I understand it, this was done deliberately to avoid issues with cable length and voltagedrop and signal degradation (which you run into anyway when using USB extension cords). There is also the hermaphroditic connector, which keeps the sides the same, while still allows extension cord use. Don't know if anybody ever implemented that.
