Up until now the DE Ladder has had no purpose. Do you remember the KoTD boom when people were really grinding that 1v1 ladder to try and get into the tournament?
Now imagine you can't avoid players that are better than you. Are the players going for the qualifiers going to grind that ladder now? Seems likely. Are they going to get more pissed off at drops that loses them points? Seems likely.
I remember a few very good players kind of got shafted in KotD2 because of artificial inflated rankings. Yeah, it's not as easy to inflate your ranking on DE but it's still fairly simple.