Say what ya will about achievements and trophies they have proven to be a success and keep players envolved and add to the cement that console ecosystems have become in the digital age.
Like them or hate them, who does them the best and does Nintendo need to implement a system to fill the gap? doesn't have to be a completionist system, it could be just a tracker or a system wide leader board between friends anything really in the persuit of cementing people into the ecosystem through a false sense of accomplishment.
I think the obvious answer to the first question is PlayStation and they stumbled upon gold, no pun, when they designed the Platinum system. Leagues ahead of the competition but still in need of servicing, refinement and features and for the love of God make DLC a separate sublist with its own percentage meter.