Although it's a good show, they only play the popular songs so it's usually repeating the same ones such as SNSD, KARA, 2NE1, Super Junior, MBLAQ, etc. They need to show some of the debuting groups (there's been like 30+ new groups this year alone). Most of them will usually disappear because they don't grow a big enough fanbase in Korea. Here's an article from AllKpop on the 27 girl groups who debuted this year and how 2 stood out:
http://www.allkpop.com/2011/09/out-of-27-girl-groups-who-made-debuts-in-2011-2-shine-the-brightest. None of them have been on PopAsia though.
And there's usually a few groups that have been around for a while but don't get a mention... now that I think about it, Jewelry is the longest running group having debuted in 2001 (and they're still active i believe since their new sub-unit "Jewelry S" released a song today) and they haven't made an appearance yet.
So yeah, you'll only keep seeing the same groups on there. While that's not bad, it does get boring after a while. It's a good way to get into asian music.