I think the very clear goal is to not avoid unreasonable skill gaps. So, for example, Luxembourg, Belgium, easy trip. Bosnia and Serbia, very easy trip.
But then we are back to the scenario aquaregia mentioned, where nobody is going to bother to organize these friendlies at all because what's the point of playing the team you score on/can score on you at will? And that's not considering how likely, for example, Serbia vs Bosnia
friendly game is politically.
Regarding the latter part, I think that's what we are discussing here. To me, what IIHF has currently is an idea rather than a well-backed (in terms of research) plan. That's why I'd wager this will all crumble when they actually start doing said research.
While lower-division tournaments might put a real strain on the federations of participating countries, the new 2nd tier tournament would do just the same. As Albatros pointed out before, we are talking about a tournament that lasts multiple weeks, needs multiple arenas, hotels and hospitality infrastructure which would hugely limit the number of cities that can organize such tournaments, etc. That's the crucial part. I'm yet to hear a single legitimate argument in favor of such a tournament.
Under the current format, everyone can organize and attend the event with relative ease. That's why U18, U20 tournaments work the same way. It's built around the idea of fitting all games into 1 week and 1 arena. But the difficulty and cost grows exponentially once the tournament grows in size.