http://www.nerdacy.com/2013/11/07/ma...ing-franchise/
BioWare and Mass Effect series Executive Producer Casey Hudson said, while commemorating N7 day today, the reason they are continuing with the Mass Effect franchise even though the Shepard story line is complete.
“It’s the idea of exploring a vast universe: going out and seeing amazing new things. It’s scale: seeing new planets, new species, and having choices that matter. Because it’s a story, and one that you care about,” Hudson says. “It’s going to continue on, and the things people love about Mass Effect they’ll see even better in the next generation of games.”