The best places on the Atlantic coast are easily El Jadida, Essaouira and Sidi Ifni and a few smaller villages
Taghazout, is grotty personally I wouldn't bother even stopping. South of Casablanca the coast is fantastic if you get off the main roads, except through Agadir
Essaiuira is very touristy now but I always spend time here, have done for the last 15 years
Suggestions
Arrive Marrakesh – Day 2
Marrakesh – Essaouira
Beach Rest days – Day 4-5
Essaouira to Tafroute
Tafroute to Zagora
Zagora – Merzouga
Saraha Trip - Day 9
Merzouga – Todra Gorge
Todra Gorge to Midelt
Now you can get from Midelt to Chefchoen in a day but it's a long one so may be stop in Fes?
Rest day in Chefchaouen
Chefchaouen – Asilah
Asilah – Marrakesh
Tour Marrakesh
Depart Marrakesh
That would get you your beach day, a bit of coast, Anti Atlas, Desert Higway across to Merzouga, Sahara trip, Todra Gorge/High Atlas Traverse, MIdlle Atlas and the sights of Marrakech.
You had a lot of rest days which I haven't included in my suggestion but some places you had a rest, probably isn't worth it so use those days some where worthwile
|