There was mention of a Challenge Cup equivalent but no details were released on it. The fact that there's mention of a third tier developmental cup would suggests to me that the Romania, Spanish and other non 6Ns clubs will be excluded and pushed down a level.
Nothing has been released about qualification for either competition but just looking at the maths, there are 38 teams between the 3 leagues, 20 will qualify for the HEC equivalent. That leaves 18 teams. If they want to mirror the top tier competition then they would need 2 more teams.
For Pro12 it would probably be automatic for those who don't qualify for the HEC. For England and France they'd have to decide if it goes on league position for everyone or if they exclude relegated teams and replace them with promoted teams.
I hope there are at least 2 teams from outside the 6Ns countries in it. My understanding is that the English teams didn't like having to play these teams as they were running up cricket scores against them. However the same argument was used to try to exclude Italy from the 6Ns and Treviso and the now defunct Aironi from the Pro12 and HEC.
They may not be title contenders but they've shown they're no longer a guaranteed 5 points and if you take them lightly then you're in for some embarrassing headlines. It won't be too many more years before Treviso are expected to win the majority of their home games and at that point they'll be a decent bet to sneak a knock-out spot.
My biggest worry with the restructure is that development has been completely shunted to the side in favour of money for the big clubs.
I just hope that Sarries don't win the last HEC in its current format as they are the main club behind its demise. Following yesterday's results I'm first hoping for Munster to win the HEC and failing that anyone but Sarries.