Either way you're shooting enemies. I don't see how it makes a difference.
I don't know how to respond to that. It's effectively saying every game is identical, because you're shooting enemies
Space Invaders or Gears of War? Either way you're shooting enemies - It doesn't make a difference.
I'd prefer it if they did something a little more ambitious if they had to include multiplayer. Why not some Cerberus-based co-op missions? Objective based, exploration-style things (like the second half of the demo, but from the other side, and before Shepard turned up)? Then they could add your basic, boring Cerberus vs Alliance deathmatch rubbish, too. Or a counter-ops style thing. They could set the multiplayer at any point between the three games, so they could even revisit classic scenarios from another angle. A mission playing as the Salarian squad on... Virmire(?), for example.
There was a wealth of things they could have done. They went for a Horde mode