I think a general definition of technical, to be further qualified by area, would be that succesfully riding the trail requires the rider be able to consistently do the following where failure will most likely cause damage to the rider and or bicycle:

- track stand
- bunny hop
- manual
- change direction 180 degrees in very confined space
- move bike laterally or rotate bike without covering much distance
- control front and rear traction with front wheel either far above or below back wheel
- control front and rear traction in loose or unstable trail conditions due to rock, mud, sand, loose dirt, water, snow, ice
- move and maintain rider CG to almost anywhere on, over, beside, behind the bike
- negotiate significant vertical changes in the trails elevation due to rock, trees, roots, creeks, or other obstacles

The subjective part of the definition might be where each rider, (based on experience, age, attitude, ego, what they had for breakfast, the bike they are riding), defines for themselves (or the group they talk into going along on the "not so technical ride") what it means when you say:

- bunny hop - how high?
- manual - how long/how high/going uphill-downhill-level?
- front wheel either far above or below back wheel - how far is far?
- significant vertical changes - what is a significant change in feet and/or angle?

A geographic qualification might be:

in the Pacific NW: a technical ride would include the need to ride thru waist deep semi-frozen water with a loose mud bottom
in SoCal: a technical ride might include the requirement to ride single track thru knee high dry grass where you can't see the trails nor the rattlesnakes