Very interesting story that fully lives up to the premium drama standard we all enjoy in the Cryptocurrency news scene...
It might be difficult to decide if Mimms' claims are justified or not. However I would not be surprised if they were. A different question is, if the "stolen ideas" can be considered an integral part of the Ethereum project.
Regardless, if you ask me, the Ethereum project will likely falter and fail in the foreseeable future. It is too complicated and insecure to be successfully maintained and marketed. Its features will be absorbed by multiple Bitcoin 2nd-layer projects like rootstock, that are tailored to specific usage scenarios and are leveraged by the network effect of Bitcoin as the strongest and most supported cryptocurrency.
ya.ya.yo!