The World Cup is a rather different kettle of fish from the ACN though, and would involve a FAR larger proportion of top level squads missing from right across Europe.
It won't happen.
Even if we didn't qualify, you must be mad to think it wouldn't affect our leagues.
Would United, Chelsea et al really stand for having (as an estimate) half of their squads missing for 6 weeks in the middle of the season? Not a chance.
Playing it in the Summer would be utterly dangerous lunacy, and playing it in Winter would cause chaos for all the big (and influential) clubs, especially in Europe so I think that's a no-go.
I think it will be moved elsewhere.