you have to consider first size too !
for example some release of Funi has some shitty encode and they are big !
something like 700 MB and when they re-encode it might be the best result they could achieve !

Think of it this way; smaller size if you want the same quality of 8bit, larger size for better quallity.

I think that what you are saying is that certain groups have achieved an acceptable level of video quality -in their judgment and yours- with a certain file size using Hi10P, so why can't all the groups follow their example?  The answer would be that different groups have different priorities and ideas about what an acceptable level of video quality is.  Someone with limited Internet service in terms of speed or transfer amounts would have one set of priorities.  Someone who plays programs on a big home theater screen might have different perceptions about video quality than someone who watches on a laptop.  So try to find groups that match your needs.

But I think focusing on file size is a mistake.  It's the quality of the translations or modified scripts that really makes a program interesting or not worth watching.  Follow that.  

“Encoding, a skill quickly acquired.  
Japan, subtle as Spring sakura.
Translation treasures!”

Title: “Homage to the Moral of Haiku: Sucking Less, Perhaps”