I just speed them away but if its multiple people on low I amp the heals or if both teams are low.It just depends on the situation. There is no real definitive answer, just sometimes they need the health or they are dead anyways, sometimes they need to be out the way of stuff faster. It's a judgement call.
He doesnt really explain what each hero is good against and what your plan should be. Not clearly. And half of them are super brief. If this is supposed to be a basics guide, it isn't actually detailed enough for newcomers or low ranked players to get better and it isn't technical enough for good players to really improve.
Yeah that makes sense. He also think Zarya is the best hero and has the best ult but that can be argued against I think.