Unless you fit a TALAS, U-Turn or Magura Thor which you can wind down to 100mm for steep climbs. Best of both worlds. That said, i have 140mm forks on a full susser and my Cotic Soul but never reduce the travel. I find that by the time the hill gets steep enough for the front end to get vague, my legs and lungs had already given up in favour of walking.
Remember kids- Slack is not a crime!
SJ