Nobody said they weren’t important.
Course delivery and design are always constrained by educational goals and available resources. If the only available medium is on-line and you want to foster/inculcate verbal skills, you’re going to have to find software that will let you do that and plan accordingly.
But you were mentioning body language, which means it’s not just verbal skills (and as someone who’s taught blind and deaf people I would never lump those as one thing). Otherwise you could happily hold discussions over VoIP conference calls and be done with.
If on-line is still mandatory for delivery but you want readable body language, you’re going to have to limit discussion group size and break everyone into smaller groups, maybe even set up separate tutorials.
If you have to have large groups of people discussing things at once (and I’d question that, because large groups of people inhibit cogent discussion, but okay, let’s say that’s a constraint too), but also have readable body language… wait, why is this on-line again?
On-line is wonderful for discussions not happening in real time, for self-directed learning, for long distance education, and for presentations which will be recorded and played back later. They are not a panacea.
As holding a small-group tutorial in a 500-seat lecture hall is inappropriate, so jamming all educational outcomes into an on-line format without thought for how the medium will affect delivery is inappropriate. It is not the medium’s fault if it gets selected to do what it’s not made for.