They disabled the radar to ease the server load. It's broken on purpose.
If that's true then I'm personally okay with it staying broken until it can work without server issues. Because of my daily schedule and what not, I rarely have time to literally wander around looking for something specific, so it doesn't bother me that it's broken for now. I understand why it's frustrating for people who do want to search out specific stuff, though.
Trading is an exciting and interesting concept, I'll welcome that when it eventually happens. I'm assuming you'll need to be in range of someone to trade with them, which again helps the social aspect of the game. And if they successfully implement trading, battling each other is only a stone's throw away surely? Again, an interesting concept.
I'm not sure about everyone else, but I am finding healing and reviving absolutely fine in game - I am inundated with Super Potions and Revives to the point that I had to discard some the other day to make more room in my bag for balls (which I actually needed). Maybe I'm just not challenging as many gyms as some people, though.
Personally I'm more pleased with the game these past few days. I have had
some issues logging in, but once I do manage to log in the game isn't crashing on me at all. No more of the mid-capture crashes or Pokéstops refusing to work properly.