My memory was that they went from the Infiniti G35 to G37 as a "refresh" but upgraded its powertrain. Something like that is necessary with the QX60. It was back of the pack in this department when the car was released in 2013 and with the new Volvo XC90 T6 and upcoming Audi Q7 (both of which do 0-60 in about 6 seconds with good fuel economy), it's going to really fall behind. But it's doubtful Infiniti would make that move.Usually minor refreshes are, as you mentioned, upgraded front ends, headlights, taillights. But there could be minor interior tweaks as well, biggest may be the audio head unit. Maybe they'll upgrade it to be more in line with the newer type units in other Infiniti models. Not a huge deal but still something to consider for those who may care about that type of thing.
Maybe Infiniti doesn't really want to compete with the Q7s and XC90s of the world but is content competing against the likes of the Enclave, Acadia Denali, etc.