Regarding the actual content: If adopted as proposed (which is unlikely), it would force owners of the 30% of least energy efficient houses (compared to the national, not EU-wide, housing stock) to upgrade their houses to come in line with the next higher energy efficiency class – by 2033, so ten years from now.
I own several buildings, both quite old (1960s), as well as brand new (net-positive energy). Improving an existing building in the worst energy efficiency class to come in line with the proposed standards is in most cases an expense in the low five figures, which (at least in Germany) will be subsidized with up to 50% of the costs. Lower energy consumption will in most cases pay for the renovation within a few years. Many of the measures (i.e. new heating source and radiators, new windows) would have to be done on those houses anyway, because the old systems reach their end of life.
So what are people complaining about, exactly?