Just finished watching Marcella and I was so bored by season 3.
Season 1 and 2 are pretty great whodunit mysteries with many twists and turns to keep you guessing. Some super dark stuff thrown in there too and got me emotional on a couple of occasions.
Season 3 feels like a terrible spinoff where not only is there no real mystery, you'll dislike all the characters, including the 2 main returning character. It feels like an 8 episode single episode. You could probably watch the first and last episode and not really miss anything.