A litte puzzled by your question.
ME3MP didn't have it. Why would you expect it in DAMP?
And how would you have time to type stuff, you're in battle...?
With a headset/mic I can just flip my mute button and talk - instant communication
If many PC players didn't talk on that platform then that's rather up to them.
Had a good chat on Xbox from time to time.
It's pretty clear that the game mechanics are designed to operate uniformly across platforms.
Mass Effect 3 was special in that it was quite possibly the only multiplayer PC game that did not possess text chat. Not everybody on PC possesses a mic (I didn't) and not everybody was willing to use one anyway.
There was an uproar because the button to activate text chat was present during the pre-release demo. When asked about why the button did not work, BioWare assured us that it would be fixed by release. The way they fixed it was by removing everything to do with text chat, thus prompting one of the longer petitions on the old BSN forum.
At the very least, a lobby chat would be enough to have some basic coordination in place before a match.