If the person wanting to end their life is above the age of 25 and has consulted 2 separate psychologists who both agree the person is sane, not doing this under duress and has shown to have put genuine effort in improving their life or enjoyment of it, then I see no problem.
For something like this to be put in place, there needs to be clear guidelines. You can spend your life debating the morality of it, but when it comes to practical application, the main thing to consider is who can cheat the system. Emo, lazy, beta, fat teens with shitty social skills who can't be bothered to learn to communicate properly? No. The mob who threatens you to go through assisted suicide or they'll kill your family? No. People with curable, but serious mental issues? No. People in their early stages of adulthood, down on their luck, going through depression and not seeing a way out? No.
It should be reserved for people who despite their ACTUAL best efforts, continue to be unhappy. Have matured enough for this to clearly not be a phase they could have grown out of and simply choose to end it.