From tumblr user inotrope:
". . . what gets me most about this interpretation is the softness. When I read the poem, I read it as exultant and fierce. The tiger within was the tiger burning bright of another poem’s fame. The tiger destroyed his cage, and who knew what next now that he was out.
Here, we’re given an answer. The tiger steps out and is surprised by the soft grass under his feet, delighted, goes wide-eyed with wonder, and leaps into the meadow. Here, the focus isn’t the cage’s destruction, but getting out, being out, so that the last glimpse we’re given is the tiger now tiny (and joyful!) in the distance, surrounded by the wide green expanse of freedom."