Fine, it was a bit formal argument anyway. And just to make it clear, I totally agree that what you describe solves 95% of the cases!
I just thought that if it is to be changed anyway then why not choose a way that really makes sure no one hurts herself. Some people will throw it away (before or after accepting the quest), drop the quest (if they took it) and get stuck again. Not many, but still.
If I were you, I myself would simply not choose a solution that solves a part of the problem (even if it's a huge part) if there is another not too complex way that really solves everything. If the quest is given by an NPC or if you can hand in the previous quest only after you have _finished_ the statue quest, then there is absolutely no scenario in which someone would block herself from the remaining part of the epic quest line. Whatever you do, whatever you throw away, whatever quest you drop, you can always start again and go further. But if the only change is, as you describe, that the statue does not vanish after handing-in the previouis quest then there will be ppl who will get blocked. Not many but still - I would not choose a solution that means extra support tickes. Even if we can all reasonably expect that this will not happen on a regular basis, I think we can all agree that this will happen: if there is a way players can hurt themselves, some will.
PS: And well, yeah, besides being pretty dumb anyway, also as a rule I try to avoid reading items' descriptions, you see.