I just went through my entire Wii calendar. There was so much lost potential. I hope Wii U still keeps records of your play time. I loved reading about the medals I earned in Wii Sports ad Wii Play. Seeing messages about how my mother reached Pro status in Wii Sports Bowling evoked memories of those first few weeks.
The biggest thing they can improve is the Friend Code business.
Since release, I've only added six or so friends. Being friends didn't even offer that much. Messages were slow and cumbersome. Both individuals had to input the code. Messages could only be read if the date ia set to the day they were received. You could say it felt isolating. I wrote several memos on each day Brawl was supposed to be released (that was a good laugh). I only inputted my family's birthdays that first year. The only games that sent messages were the Wii line of games and Mario Kart Wii. By 2008, most messages were just about the Check Mii Out Channel.
If MiiVerse allows easy connectivity between games, specific friends, general players, and family, I'll be very happy.