Creates a massive barrier to entry for any nations wanting to host the tournament. Extra teams and games per day increases the number of stadiums required, increases infrastructure requirements for transport, accommodation, entertainment / hospitality, increases resource requirements for law enforcement and security, medical care and so on.
Presents opportunities for more sports washing by wealthy nations, and sets up a tournament that might eventually cycle round a select few nations that can afford it or have the infrastructure in place, a bit like the F1 circuit.
Growing up the world cup was a big deal, in part because it was on terrestrial tv and we didn't have satellite / cable, but also because international football felt more prestigious. Now I find myself not actually watching many tournament games due to feeling fatigued by the amount of club football on all the time, and international football has been watered down too much with pointless friendlies.
Can't imagine this is going to be good for the game.