Hell, Kyle Raynor could take on all 15 of those pre-crisis. Same with Franklin Richards. Cosmic Spidey, Wolverine, Lobo even.
Seriously, the DBGT/Z characters just arn't that strong compared to some of the characters in the DCU/MU.
The 10 listed on the front page could easily wipe out every character that is in the DBGT/Z universe without even trying.
And, I'll remind you. People in the DBGT/Z universe are stupid. They always start low, then say "WELLL WELL WELL LOOKS LIKE I HAVE TO USE MORE OF MY POWER!" about 20 times before they finally go "IM AT MY FULL POWER AND I CAN BEARLY BEAT HIM!". DCU/MU doesn't do that, most of the time. They just go "**** fair fights, I'll use my max from the start."