I don't know how things worked in the past, but details for this event are underwhelming.
The last time they did this, in 1990, they hit 29 cities across America, and spent 3 days in each city (except LA which got 2 weekends,for 6 total days). Each city had 3 finalists, one from each age group, move on to the World Championship stage in Hollywood. That's a total of 90 finalists.
Here's the info from Wikipedia.
The Nintendo World Championships had three separate age groups (11 and under, 12-17, and 18 and over). The city contests were held over the weekend and began on Friday afternoon and ended on Sunday night. Over three days, players qualified for the semi-finals over two rounds. The first round a player had to score at least 175,000 points in the "Pods" area. To qualify for the semi-finals held on Sunday night, contestants had to play on a seven player stage and score at least 200,000 points.
On Sunday night, the semi-finalists were divided by age group, and each semi-finalists group played in the "Pods". At most, 100 could play at a time. The top seven scorers from each age group then played in a final round on stage while Terry Lee Torok, Steve Werner and John Michael Phane moderated play by play to the crowd. Out of the seven scores, the top two scorers played head-to-head for City Champion.
The finalist won a trophy, $250, and a trip for two to the World Finals at Universal Studios Hollywood. The runner-up won a Nintendo Power Pad and a Game Boy.
The world finals were conducted similarly to the city contests and were located at Universal Studios Hollywood. Each age group's thirty finalists played one round for the top seven positions. The 18 and over group played first, followed by the 11 and under, and completed with the 12-17 age group. Each age group's top seven played and the two top scores played head-to-head for the age group title.
So yeah, the 2015 reboot is way underwhelming. 8 cities total, and 8 city finalists + 8 "special guests". That's nothing compared the 1990.
And the worst part of this whole thing is that they've announced the 8 qualifier cities just 11 freaking days before the events. So if you want to participate and don't live near one of these cities, you have to make last-minute travel plans. Good luck finding an affordable flight and getting any time off approved on such incredibly short notice. It's just downright insulting to their fans to handle it like this.