Very good choice of words, but I have the following remark. The use of "besides me" suggests sharing, whereas the Arabic expression suggests substituting, which goes well with the closing of the verse.
Great point, especially the matching between beginning and end of the verse. Only problem is that linguistically, من دون
means "besides." Recall that the primary issue of the disbelievers is not denial of God, but sharing
devotion to Him with idols.
With that precept, I think that the epilogue of the verse means, "How wretched an alternative to monotheism!"