I find the arguments around improving our democracy that focus on improving turnout first kind of frustrating. There's really no reason to believe that a uniform increase in turnout would actually result in substantially different outcomes. Yes, older and more conservative people are somewhat more likely to vote, but a) not *THAT* much more likely and b) there's no shortage of conservative youth either. The combination of those two things means a difference in outcome of maybe a few points here and there.
But it's also trying to cure the disease by treating the symptoms, like dunking a person with HIV-related pneumonia into an ice bath because they have a fever. Turnout won't improve until the system counts every vote. Turning back the clock and going back to a two party system will continue to leave voters disaffected as well, since many will be left out in the cold for a party that affects their views (probably especially minorities).
The only answer is PR.