I'm fine with a prequel, as long as it doesn't have Shepard. Shepard's story is done.
Prequel or 2 hundred years after the end of ME3.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix