Eh I think... its more or less the "veiwers choice" trend or more or less for us that download it... "what we find" trend
I' m pretty sure there are alot anime we've not seen in the USA released in japan, just the ones that have enough money, and or good enough/chosen to be aired.
/insert random anime video character/scenes from 9 differnet anime (I cna post more anime pics but too lazy XD)
Every one of the above anime.. have a different type of "theme" of action etc. In fact the main character dies in one the above anime (technically)
oh and the anime slisted above are...
Busou Renkin
Kiba
Black Blood Brothers
Dr gray-man
Tokyo Majin Gakuen Kenpuchou
Jigoku Shoujo Futakomori
Shin Angyou Onshi
Jyu Oh Sei
Bakumatsu Kikansetsu Irohanihoheto