We do know that combat is to be released in stages. Coming out soonest is going to be combat on the ground (NPC squads with guns), and perhaps creature combat at the same time.
After that, anyones guess on timeline and feature. Space? Vehicle? Whenever it gets done.
--Arch , out.
The Combine is programmed by a small team of amateurs in their spare time, so you have to understand that we can't get everything done perfectly at once. There's a laundry list of items that must be finished before true, player-vs-player combat can be released, which are coming as fast as possible. That's why it's impossible to put an exact date on anything.
"Soon(tm)" is an overused joke/cliche around here, in that soon used to be used to mean "we really do intend to implement this soon", and reality became months/years with nothing appearing. So the (tm) was added to signify more of a "we want to get this done, but we don't know when".
Hence my "When it's done." which is probably the best answer anyone can give at the moment.
"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."