Part of being prepared IS being equipped appropriately rather than being not equipped.
Agree that you should pack for the expected conditions with perhaps a reasonable margin for error, but when you hike someplace like the Southern Alps of new Zealand, it is often impossible to predict the conditions, so the margin of error becomes larger than, say, a summer trek in the Sierras. Unpreparedness (as in lack of adequate gear AND the knowledge to use it) is a big killer of tourists taking to the backcountry in NZ. Many don't appreciate how rapidly and without warning things can go from a very nice summer's day to a sub-zero blizzard and whiteout conditions that may last for days...or from small side creeks to enraged floods even when it hasn't rained where you are hiking. People here also get into trouble from lack of equipment because they plan on making it to the next hut. If events arise that interfere with that plan, it can rapidly become a life-threatening situation.
I must admit that most of my lightening up has not involved much in the way of being 'less equipped', but more from merely finding lighter equipment that does the same things. My bag still needs to be safely warm below freezing, even in summer. My tent still needs to withstand gale force winds, my pack still needs to deal with off trail abrasive bush-bashing while carrying my load comfortably and my mat still needs to insulate me from the ground. My stove still needs to cook food in a reasonable time in strong winds and rain, and my boots still need to protect my feet from pointy sharp plants, scree and river gravel. Most of my equipment I could clearly live without, but choose not to for the sake of my enjoyment. This includes a fully enclosed tent to keep biting insects at bay, trekking poles, a rain jacket and a windshirt. However these are also much lighter than I used to carry. I now tear my trail books down the spine to make them lighter, but I still bring something to read. My light is very much smaller and lighter, but I still bring a light and spare battery. And so on and so forth. I still agree that knowledge and planning are the front-line preparedness requirements, but I don't skimp on the equipment either!