Having seen the orderly arrangement of things on bitcointalk and how matters of scam are taken very seriously, I think there is no need for more forums because the more forums we have, the more likely scam activities in the crypto-world will occur. Of all the forums I have seen, bitcointalk is the only one that has a measure to fight scam. The rest just take fees and promote projects on their forums without any checks. (On bitcointalk, we believe everyone has the power to take action when a project seems to be a scam for the higher members of the forum to work on.)
I understand that blockchain and decentralization move together and for that matter, more forums for cryptocurrencies discussion should not be a big an issue but with the recent scam projects ongoing, my opinion is the leave everything in the hands of one forum to handle all ICOs discussion there.