Why does it matter where Slovaks best developed 20 years ago? Finland has arguably had the best youth development of any country in the world in the last 5-6 years. Why would Slovak players participating in their youth program be unable to progress the same way the finnish prospects are doing?
And why look exclusively at the history of Slovak players? If Pastrnak and Vrana could come through the Swedish system, then so could a Slovak player. Doesn't matter if they are Czech. They are much better indicators than Gaborik or Sekera who came through the CHL a very long time ago.
Swedish and Finnish players who opts for the CHL usually does it because they don't think they will get enough of an opportunity in the SHL or Liiga. Those who are good enough for a decent role at the men's level usually stays. Fehervary was good enough to make the SHL, so he stayed. Same with Jaros and Cehlarik. Maybe Daniel Chovaniak and Marcel Stefancik will be a different story, and moving to the CHL could be in their best interest, only time will tell. The same goes for Slafkovsky. But if he's in a position where he could be a top 9 forward and play PP minutes in Liiga, I don't see why he would move to North America all of a sudden.