BioWare... I normally love everything you do, and have always supported you. I even hope to work for your base in Edmonton, after I graduate from college (I'm a fantastic animator, and you'd be lucky to have me), unless this continues. You can't keep letting EA infect your games like this; they're turning your company over to the Varren, and making Revan hold his head shame. Multiplayer, unless it's implemented extremely well, and does not detract from the single-player campaign at ALL - which I highly doubt - is always a poor feature to add in games like this. Games like yours.
Now either I'm right, and it is EA that's "heavily suggesting" you do this, which in that case, I have lost the last shred of respect for EA that I desperately clung to for so long. Or I'm wrong, and you want to give multiplayer a shot. But if that's the case, why the hell are you experimenting with multiplayer on the final game in an amazing trilogy, instead of on a new, unknown series, where it doesn't really matter if it bombs!?
Either way, this is a bad idea, unless it really is going to be a perfect form of multiplayer. So I hope you can perfect multiplayer on your first try... I really do.