Mid model vehicle updates are very predictable. Updates to end of model are also fairly easy to predict. If I were a betting man I would guess:
Mid cycle refresh (2013-2014)
1. Redesigned Grille
2. Redesigned Headlight shape
3. Maybe redesigned front and rear bumper cover
4. A few new exterior colors added with possible deletion of one color.
5. Maybe slightly redesigned interior or dash
6. Possible LE or TE delete with addition of Sport or Special Edition model.
7. New wheel designs
End of 5th gen (2017-2018) will see:
1. Really cool headlights (projector or LED) and taillights
2. More color changes
3. New electronics
4. Updated interior
5. New wheels
6. Front end redesign
7. Rear end redesign
From my observations throughout the years this is the pattern most OEM's follow. Why?
When they bring out a new model the "newness" of the model is what attracts buyers. As these new buyers start to dwindle updates such as colors, wheels, front end design, new packages are introduced to "excite new buyers or entice existing owners to sell and re-buy. As model generation nears the end all the goodies like high end electronics and lights are introduced to try to get the last customers interested to buy a 4Runner.
Is this what will happen? I do not know but if history can be a harbinger of things to come then some combination of items listed above will happen. Notice I DID NOT list Manual transmission, diesel option, etc. Those would be out of the norm for an OEM offering.