IMO it's really bad. They win everything, no new EU and NA stars are developing, only KR ones.
It's really strange to see Koreans in NA and EU finals, when it's supposed to be EU and NA only, you know?
Blizzard should ban koreans from playing in EU and NA tournaments or let them play, but they will need to actually live in EU or NA, not to have a little trip once a year to win some ez money.