an article from momoedgewood..
A story I read on gossip magazine Cyzowoman this morning also talked about how some Johnny’s fans were worried about the news. While I can’t guarantee how true the information is, it quotes several journalists and fans saying they’re worried Kis-My-Ft2 aren’t ready for such a huge venue. It reports some fans being upset because older Johnny’s groups like SMAP or TOKIO started off at smaller venues and gradually worked their way up to Tokyo Dome status after getting more experience and fans. To start from the top might hurt the group’s reputation if they don’t sell enough tickets.
i really don't know anything about tokyo dome except that it's the biggest dome in japan and jump performed their debut concert there, so i read the information regarding tokyo dome in wikipedia..
notable performances [inside johnny's only]
On July 22, 2007, Kinki Kids held their 10th anniversary concert at Tokyo Dome, which drew a crowd of about 67,000 fans, making it the biggest concert ever held at the Dome. The record was previously held by Tsuyoshi Nagabuchi in 1992 when his concert drew an audience of 65,000
On December 22, 2007, Hey! Say! JUMP held their debut concert "Hey! Say! JUMP Debut & First Concert Ikinari! in Tokyo Dome". They became the youngest group ever to perform in Tokyo Dome average age 15.2 years old.
In August 2008, KAT-TUN broke the record for the longest consecutive days of concerts, when they performed at the stadium for four days in a row. Less than a year later, they broke their own record with concerts eight days in a row from May 15, 2009, as they sold all tickets immediately.