I understand it as more of a cup, or a mixed tourney, with group stage and then play-offs. I think that is how the scandies play it.
the normal league goes on in the meantime. and like this, we don't have this uesless football-less time in spring, where we have no teams left in the euro-cups, but our teams can still practice on international level. and I also think, derbies like ferencváros - sparta are spicey enough and attract many spectators, although I hope ferencváros is not in it
so, from those mentioned countries, these teams would be in it, if it starts now: MTK, Zalaegerszeg, Debrecen; Dinamo Zagreb, Hajduk Split, Varazdin; Zilina, Artmedia, Ruzomberok; Domzale, Primorje, Lendava; Mlada Boleslav, Liberec, Sparta.
now these are 15, we'll need a 16th team, could be the previous year's winner or whatever, or maybe a 4th czech team, they have the best of these leagues after all. I also have to admit, those slovenian teams, well, I don't really know any of them. their only relatively known team, olimpia ljubljana is not evn in league 1.
as for austria, we don't need them. they can go anyway with all their millionaires club owners and buy themselves a spot in the champions league or buy the champions league and call it red bull league