It sounds illogical to ask for a Bengali sub board for Bengali translation and press release because we don't have any local boards yet. But the way the Bengali board is hammered with translated topics and news source posts, it looks like spamming to many of us.
well I will also support that Bangladesh should be given a local board but I don't think that these spamming issue will be solved just by giving board. Actually newbie has no interest in current active discussion and they just transalte news with one image and source link or the transaltion that you pointed out. Once the post has been translated then it should be discussed for some days to learn something. If translation purpose is just to get Merits then It is not good because it will only grow spamming.
As a native speaker, I can say that very few translators met the translation standard, and most of the translation was done by Google Translator and later edited a little bit and reposted. I can not blame global members for contributing to those topics, as they can not speak the language and have little understanding of it.
I think the better solution is that reputed and experienced members of your country approve some quality transalator and also inform the original post creator about it and whenever newbie want to start transaltion then first prove himself that he could do a quality transaltion and will not spam in the board.