I would suggest (as is commonly accepted) that building new nuclear is a net-negative for climate change (due to high cost that could have been spent on renewables, efficiency or other related stuff that would have more impact) but I'm not against keeping nuclear plants open if they are within their lifetime.

Having said that, I've never seen an actual solid argument that Germany rushed their nuclear phase-out.

It usually ends at "they're phasing out nuclear, they still burn coal, they're idiots" yet if you look at a graph of their carbon intensity, it's going down at roughly the same speed as their neighbours and there's no obvious blip from the nuclear phase out. If anything, the fact that they still have coal means they've got a few easy wins left as they phase those out. (This holds true even when accounting for carbon imports/exports).

But the whole "carbon tax" thing is about lots of small changes adding up to make an effective difference. Germany appears to be achieving this even with apparent oddities like nuclear and coal. Maybe those were the political cost of doing all the rest of the stuff.