Well you're completely wrong about Nicola Walker, she's amazing. I think the thing is in the last few years she's had a few parts where she's basically a deeply troubled hardworking professional with a lot of family bother (Last Tango, Unforgotten, The Split) so it can start to feel samey but IMO that's no reflection on her acting - it means she's been cast because the director wants her to bring a similar energy I guess. Would be fun to see her cast as a completely different type of person.
Keira Knightley isn't really suited to acting, she smirks all the time! Not sure how.
If you want to see Danny Dyer doing a great job, watch Spy. He's hilarious.
Need to rack my brains for who else is crap.