Shutting down nuclear was a pretty popular policy. But that aside, what the Energiewende was not about was removing obstacles to building out energy infrastructure rapidly (e.g., the delay on the north-south connections).
Germany could have decarbonized faster by maintaining its nuclear power, but only to a limited extent because the bulk of the coal (especially lignite, a high CO2 emitter) is burned to generate electricity in the former East German regions, which have been devoid of nuclear power since 1995 (Soviet reactors were shut down due to their unsafety). Therefore, all active reactors were located in West Germany, and there is no adequate high-voltage line capable of transporting their output to the East.
At its peak (in 1999), nuclear power produced only 31% of Germany's electricity, itself less than 25% of the energy consumed (even considering primary energy, it only provided 12.7%), and by 2011 (Fukushima...), it was producing less than 18% of the electricity.
Moreover, in the East, coal-fired power plants have long produced high-pressure steam for district heating (industry and heating many premises), which a remote reactor cannot provide.
To claim that Germany shut down its reactors for no reason (after Fukushima...) or that only a minority of environmentalists decided to do so is misleading as, in Germany, all political parties close reactors, and most reactors were not closed by "Greens".
Furthermore, this nuclear potential would result in higher costs and dependency since it would have replaced part of the huge coal industry, which is very difficult to get rid of.
In 2015, due mostly to fracking gas, the US was down to around 450g CO₂/kWh.
Germany, with its Energiewende, was at around 560g CO₂/kWh.
Because, of course, the Energiewende was not about climate change. It was about shutting down climate-friendly (CO₂ free) nuclear plants.
Both could have done better. France is currently at something like 32g CO₂/kWh and has been at roughly that level for decades.