Press F10~12 (or whatever your 'target nearest enemy/PC/NPC' button is configured to)? Granted, it's not a full target cycle, but as it targets the thing nearest to you within your target cone, it's sufficient for my purposes.

Keyboard targeting is the same as it was in FF11, as far as I can tell. I have no experience with mouse targeting though.

I'm not against any additional targeting options to players, but I'm throwing my voice in here to say that I like it how it is and if something is changed, please allow us to choose between the two.