With the league expanding it needs to find quality soccer players somewhere. I see no reason to not let teams find players wherever they can. This isn't actually letting more foreign players in, it is still 7, the same number teams are currently allowed. There is just no age limit.
The economics of it will limit the use additionally. Team's won't be able to afford 7 top level internationals. They will probably still have 4 SI and 3 YI.