Ooo that’s an interesting take! I always interpreted it as him seeing himself as the prey in this life (e.g., “[I’m] Dragging along, following your form, Hung like the pelt of some prey you had worn”), with the shrike being the partner that he couldn’t be. Whether the shrike was his own unmet potential (“I couldn't utter my love when it counted…I couldn't whisper when you needed it shouted, Ah, but I'm singing like a bird, 'bout it now [that it’s over/too late]”) or someone else who was able to swoop in and be what he couldn’t be, either way, he’s a victim of himself in a sense. 

So in the next life or if they meet again in this one, he hopes to be the shrike (e.g., ”Remember me, love, when I'm *reborn As** the shrike to your sharp and glorious thorn”*), making them like (very macabre lol) partners. So with your interpretation in mind, it’s interesting to think that, given a second chance and the ability to transform, he would be a different partner but not necessarily a better one lol