It's still all total nonsense (circuit beards aside, those are awesome). If synthesis actually worked the way BioWare wrote it, there would be massive species extinction of flora and fauna across the galaxy.
The introduction of totally new material into ALL organic life from the macro to the micro, material that requires increased energy usage, would result in a massive upheaval of all ecosystems.
As one simple example among the countless problems: Think about organic decay. Now all organic life has "synthetic" components, does it all decay? does it act like a pollutant on certain planets? that's a massive amount of new material pumped into every ecosystem, the evolutionary balance of life everywhere has been totally turned upside down.
Are processes that gave rise to species based on their evolutionary niche, like pollenation, still around? How many species have lost their evolutionary place in existance now?
These are not new problems with synthesis, the EC only re-emphasized that they are in fact canonized problems.