I like the concept of quarterly review. since I have never fully implemented GTD it seems as you write that GTD helps with vision I’m so occupied with crap in front of me I can’t forecast down the road.
As a farmer much of what I do revolves around the seasons so it's logical to review those things on a quarterly basis. I also do an even more indepth end of year review that startsabout mid December that I hope to have finished by mid January. Spreading the year end tasks out that long means I am not burned out and can really give everything deep thought. I try to do a lot of mind sweep, collection and cleaning out of old files during the first part. Processing and reviewing what I've gathered next. Scanning, shredding old files, getting tax papers ready and other clean up tasks near the end. Then a final once over where I go over my yearly plan as well as reviewing the 3-5 yr,10-15 yr and lifetime plans and all the higher levels.
Now changes happen, and the plan never survives first contact with the sheep or reality, but I have a framework of important work I want to move forward every year that is split into quarterly chunks.
The thing is I've been working in the GTD ecosystem learning and growing in my practice for 10 years. I have a long way to go but I like the path and am enjoying the trip.