I said 25-28. Only because, unless I misread/misunderstood the question, I thought we were talking about where we would draft him today, if we are starting a team. I'm not a fan of the guy, but I know there are at least four other current HC's who I would pass on before him. Not sure I can come up with eight, though, so 25-28 is where he landed for me (off the top of my head, not having gone through all 32).
If the question was to rank him on his performance during his tenure in Philly, that's a different story. He's probably top 10, easy. But, that's not the question.
Edit: 25-28. And I went back through all 32... I can come up with about 6 that I rank below Siriani, with another 3-4 that I'm simply not that familiar with. So, he's right on the fence between 21-24 and 25-28 for me.