I’ve been to Morzine loads, but always avoid the Pleney and it’s ilk so I can’t advise on the DH stuff I’m afraid, however…
And as mentioned above- anywhere with braking bumps. They are starting to reappear at Brechfa. TBH though, my advice is to ignore them.
Llanberis path down off Snowdon is a bit reminiscent of sections of the GR5 from Pointe de Mossette down to Les Linderets.
When it rains in Portes du Soleil it can get VERY slippy. Off camber stuff becomes unbelievably challenging, and the rooty sections just seem to get even rootier. So you need to find some off-camber slippery rootiness I suppose.