> There I disagree.  Classes can perform a number of useful functions not 
> least of which is "chit-chat". 
> It should, however, go without saying
> that the number of hours you put in outside of class should far outweigh
> the number of class hours.

I don't think classes themselves are entirely useless (or that they 
would actually detract from someone's language ability) - but if for eg. 
someone did 5 hours of classes each week and aimed to do 5 hours outside 
study, I think they would be better off doing 10 hours a week self study.

Factor in the tiredness from their job and attending school (leaving 
little energy for outside study), the fees, school commuting time and 
costs... overall detrimental to their life in Japan in my opinion.

Unfortunately with Japanese, being immersed in the language (either in 
life in general or in classes) isn't so helpful... it's the sheer hard 
study that really advances you.