I really wish in-game voice chat would be added. Apparently being cross-platform makes that a lot harder to implement than it would be for a single-platform game, but it shouldn't make it impossible.

A lot of FCs and static groups use third-party voice chat applications (with the console players running it on a laptop, tablet, or cell-phone). Unfortunately, the amount of coordination needed to set that up excludes having such voice chat in PUGs. PUGs are actually where communication is the most necessary, since you don't come in already familiar with your teammates' playstyle and preferred strategies. Anything that would improve communication there would be a significant boost.