We don't do SWOT analysis of strengths, weaknesses, opportunities and threats for several reasons.
We don't do an analysis exercise as distinct from planning. We don't engage people in the continued unproductive and unsustainable practice of focusing on weaknesses and threats. We don't leverage a sense of inadequacy and fear because these diminish capacity for dreaming, alignment, velocity, intelligence and creativity. We don't foster a culture that is strongly reactive to opportunities. We don't brainstorm lists of strengths independent of storytelling.
It is no coincidence that the vast majority of strategic plans fail and the vast majority base their process on the SWOT analysis. That's why we take an entirely different approach in the Agile Canvas.