The.Bard said:
They've already succeeded at doing Mass Effect sans Shepard. The books Karpshyn wrote were fantastic - and all of them were Sans Shep.
That's true, but (a) those were prequels, (b) they didn't feature the main conceit of the series - choice, and (c) it was criticized for pandering to fans of the franchise, and featuring generally undeveloped characters. They amounted to little more than set-ups for the game. That, and Karpyshyn is gone, so I doubt he's suddenly going to run back to pick up where he left off, especially after the franchise's shellacking.
Dark Horse has several Mass Effect comic storylines without Shepard. Marauder Shields has been great without Shepard.
I've only read Redemption. It was decent, but nothing to write home about. Never bothered with the rest after 3 came out.
Also, I'm pretty sure that Marauder Shields is a straight-up fan parody, correct? I've only seen cursory glances.
Even with that qualifier, it's not like the comics are much to write home about. All of them are relatively small-scale stories focusing on one or two characters in short situations. Nothing matches the scope of Shepard's story in the original game.
So if they cut Shep, I would still see it, and I'm sure others would, too. The beauty of the Mass Effect Universe is that it always felt like Shep was just a small cog in the machine, and that a vast infinity existed beyond him. So I don't think the universe is tied to his/her character at all, and viewers who never played the games wouldn't even blink about it.
The whole series is tied to him/her. Intrinsically. Shepard is the catalyst for the setup/resolution of the defining events in the trilogy. They continually hammer it home that Shepard is the only person in a real position to do anything about the impending danger, and all of the missions/decisions factor into the galaxy in some way, even if they were homogenized. This goes back to what I said about the comics - outside of Shepard, there are very few people who have the same depth and player-fueled characterization. Everything ties into Shepard' character in some way except the Illusive Man comics, and those were more setup for the game than anything else.
The First Contact War would make a lot more sense for a starting point, as we can experience the discovery of the races, the citadel, and the relays firsthand without being told about it.
Doesn't sound like an interesting movie to me, especially since the First Contact War could be boiled down to "robots fight purple people for years". If I'm going to see Mass Effect, I want to see Shepard, end of. Waiting for two or three films before we get a character payoff is a waste of time and money - they either have to do it with Shepard, or not at all.
Like I said, they've tried various protagonists in the comic/tie-in game lore, and all of them (besides Liara, maybe) have made no impact. Jacob Taylor was supposed to get a spinoff after 2, but everyone hated him in the game, and he was dialed back to a glorified cameo. The Infiltrator protagonist (forget his name) made no impact whatsoever.
... or they'll go through rewrite after rewrite and this will go the way of Gears of War, Bioshock, and Halo films, never seeing the light of day. I hope for the former, but the realist in me says expect the latter.
I truly hope it's the latter. There are some game experiences you just can't accurately replicate in a film without sacrificing a lot of the elements that made it unique in the first place. This is one of them.
I don't think it will be. 
