I spent 2 weeks in Morocco last summer.

Tangier and Casablanca are the least appealing parts of the country for me. I would pick up a cheap flight from Spain, I flew MAD-CMN in the summer with Easyjet for about 30 Euros all in, cheaper than the ferry and less time consuming

If I was on limited time, I would totally skip Casablanca, and spend time in (in order of preference)
Marrakesh
Fes/Meknes
Essaouira
Rabat

I found the touts in Morocco more obnoxious than in Turkey and Egypt, especially in the tourist areas.