I would be very disappointed if that isn't what it turns out to be at its core. That's the only place I can see a solid emotional foundation coming from.
I'm not sure it will turn out that way, though. I just recently finished my second playthrough of SotC, and my disgust with the way the ending was handled has only strengthened. You have this beautiful story that draws its strength from its simplicity, from the emotion inherent in a story about a man willing to destroy himself for a chance to bring his lover back from the dead... and then it's all nearly ruined by an incomprehensible, silly ending that apparently only exists to tie the game to Ico (which could have been accomplished in a much more effective way, if anyone had bothered to try).