We don’t call every WNT event a major. Neither does Matchroom.
Matchroom has lots of events. Some it calls majors, or Gold events. Others are deemed ranking or Silver or Bronze events. The Pattaya Open fit into that category. So did the Caraboa in February, or the upcoming Diamond Expo event in Philadelphia.
***
I generally consider the UK Open, European Open, WPC, US Open, Florida Open and Hanoi Open as Matchroom majors.
The WPC has the biggest prize fund, toughest field and a history. The U.S. Open is next for similar reasons.
The UK, European, Florida and Hanoi opens are newer, but all have the same fairly large prize funds and 256-player fields that usually attract most of the best players.
Matchroom is calling the Philippines and Arizona opens Majors, but I don’t think they are. Smaller prize funds, 128 players and single elimination.
By the definitions I use, Qatar would qualify as a major pool tournament.