You need to realize we PC users are behind the curve compared to consoles. Most MP are played with a microphone and most console players already do have one.
Text chat could only be useful in lobbies, but it's a very small amount of time to justify a big investment.
As for the sound, if you can't talk normally without waking up someone, just the key pressed on the keyboard will wake them up anyway. This also affects a very very small percentage of people during a small window of the day (22h00 to 07h00).
Combine those reasons together and it's hard to find a compelling reason to invest in that feature. I wouldn't oppose to having it, but I think it's very reasonable for Bioware to just ignore it.
Respectfully disagree on most points.
Yes we are 'behind the curve'. Consoles did not have a generation of gamers who played with text-based input, PCs did. Trying to move away from it is not trivial. You are far more likely to end up with silent players (ME3MP on PC) than people speaking. People can be missing a mic or not willing to use it, but every PC player (I hope) has a keyboard somewhere nearby.
Since DAMP seems to be also more strategically paced in terms of dungeon crawling (you pick the time to engage, not have swarms spawn as soon as previous wave dies over), players could discuss engagement strategy (if briefly) in chat before engagement. And I highly doubt that an in-game or in-lobby chat is a massive investment.
And oh, if only kids slept from 10pm to 7am, life would be such a bliss
Waking a child up with light keystrokes is nowhere near as likely as by talking on the mic. And as mentioned, confusing older family members is another drawback of voice chat.
During college years, I had no issues with voice chat. An empty room/apartment doesn't care if I am talking or not. However since then I got a family, so now I have to adapt my gaming to family schedule, which can be difficult if talking is required to play.