I can understand why people who are against euthanasia in principle, such as Clanad, would not want a law that allowed it in any circumstances.
But when it comes your more pragmatic viewpoint, v_e, what's your problem with you being provided an opt-out (or me an opt-in)? What is wrong with personal choice in this matter?
I do not wish to force assisted suicide onto you, if you don't want it. Likewise, I do not wish prolonged living to be forced onto me, if I don't want it.
I doubt the lawmakers of the country would agree with you that they couldn't frame a law. It's not really a great reason for not making a law - that it would be too difficult or have unforeseen consequences. You might say the same about any law.