I don't think you understand how easy it is for good players to get high spots on the ladder in relatively few games. And why would you want to keep anybody out? You want the best players, and as many of them as possible. Comments like yours just trigger me, sorry.
Using the ladder is an interesting way to get people to play in automatch. I think it's a weird way to quali for a tourney, sinces ladder-ranks can be manipulated pretty easily, but I understand that it's a method of getting people to play ranked. I'm curious to see how that part works out.
The ladder is certainly an interesting way. I am also looking forward to see how it plays out. Yet you are a bit wrong about that being hard to get on high places in a relatively few games. Aimstrong was back for one day and he had his rank 4 brits back, the ranking system is a bit flawed in that respect.
The only point I am making is that yes we want the best players, but we also want the best players that actually regularly play this game and don´t just come back when there is some money to be made.