I don't agree...or only in parts. As for the best 12 teams, it's good because they'll only have high level matches, but there are some mistakes in the system. Let's say Belgium wins the 2nd group and gets to play in Final Six, in the end they'll get more world ranking points than most teams from 1st group, but only because they had much easier opponents. And Croatia, Czech Republic and Bulgaria won't benefit at all from playing in this new WGP because they'll have only weak opponents (apart from each other).
In addition, I wonder what will happen to European League now that almost all European teams are in WGP. Probably it will be once again very early (June until mid July), but not many teams will want to play both competitions probably...
If relegation system works, Belgium and Bulgaria might play in first division one year later. By the way I am also concerned about the future of European League. Turkey might still want to participate since our federation want to get a wider player pool with international experience, also our youth and junior NTs have good players who can play in a B-NT. Serbia also have a wide player roster. However except those two I don't think other GP participating teams would eager to participate also in European League