Bancor should be on their own blockchain....
I dont know if this is technically possible with the goals that Bancor pursues, but if it was I agree, at the current state of affairs it would wish for Bancor to be on its own blockchain too. I guess many projects are being shown the limitations of the Ethereum network these days and might reconsider if the Ethereum blockchain at its current state is up to their business model. Time will tell, I hope that ETH fixes the scalability issues as soon as possible and get back to normal working mode.
If you want your transaction to go through you have to set at least 40gwei at this very moment.
The whole point of Bancor network was to connect hundreds of erc20 tokens, and it was possible because all of them are based on ethereum. So right now building own blockchain isn't reasonable, since cross-blockchain transactions are still in developement. Maybe in the future, when it will be a standard.
Exactly. Bancor aims at providing liquidity cross-blockchain and thereby solving the "double coincidence of wants" problem.
Building an own blockchain is not the priority at the moment.