i know the KA1 had some blotchy light issues but i don't recall any light bleed/screen problems with the Kobo H2O Edition 2 i'm sure someone will correct me if i'm wrong.
regarding the Kobo Clara HD what is and isn't acceptable will obviously differ from one user to the next. hopefully the light bleed that some have seen will be the exception and not the rule.
time will tell it always does.
best wishes koboy