The issue with top 10 regardless of country is that until recently (and to some extent, it still happens), most international teams can't compete at the same level as the US teams as cheer isn't as big in their country, or hasn't been around as long. I feel that even in Canada, we're only just starting to catch up fully with the US teams int eh International divisions. If I knew that I was travelling around the world for a 2:30 min routine and no shot at anything else, the draw wouldn't be there for me. I see it as comparing a great high school basketball team playing against a NBA team. Both may be great in their respective division, but the HS team will always be crushed by the 'professionals'.
Until cheer sees more equality throughout different countries, I think it needs to stay as top 3 from each. And yes, I have been on the losing end of that by missing finals by .5 and watching X-All Stars from random country make finals over us when we scored 30 points higher.