PC didn't get the Old Ones Army at 1.3 either, so we must wait, however, I don't know for sure if PW is doing PC or not, if they're committed to Terraria's Console/Mobile only (Yes, I assume they have other projects, other games, other companies that they work on/with) then it may not be too long.
Yes, that update (1.3.5? Was that it?) adds some stuff, but it's basically an Event, a few items, a few blocks, (Traps, mostly) a few monsters, and like 1 NPC...I haven't played it, but it doesn't seem incredibly large, at least comparitively to 1.3 itself, my point being it might not take very long, and I bet Console/Mobile can get that one at the same time.