Hot and cold... If you want him to just keep the ball and nothing else, then you might as well sell him... He's a risky player, he tries things, and when he's producing 5 or 6 truly world class moments in a game I think occasionally losing the ball can be excused. One time he might lose the ball but the next time he'll create a goal by doing something that no one else would even think of trying. That's the player he is.
Ok, let's agree that there are lots of different levels between:
Passing sideways all the time and trying a killer ball in every single action.
In simplest:
1) players who never risk
2) players who play a mix of risking and passing safe passes
3) players who risk all the time
For example, Messi, Xavi, Iniesta, Ronaldinho, Etoo etc are all players who played a mixture of safe+risk passes.
The thing is: Xavi/Iniesta WON'T play a risky pass in every single opportunity, with an alibi: but no one else is trying risky passes so I had to do everything.
Someone already mentioned a few pages ago, this is how Messi plays (but I would add: Xavi, Iniesta also)
Ball 1: there is no space/options for a successful risky pass=they pass it sideways and wait for a better opportunity
Ball 2, 30 seconds later: still no options, pass it again
Ball 3, 30 seconds later: xx teammate is in a good position=they try a risky pass, and now you have a high chance for a success.
All you had to do was to use your brain and IQ (I am talking about players) and wait for a perfect moment.
So, these are smart players with good passing skills, who wait for a good moment and then they try a risky pass.
On the other hand, this is how Neymar's IQ and decision's making works:
Ball 1: I will try to dribble past 5 defenders or try a risky through ball for Suarez/Messi
-- he loses the ball
Ball 2, 60 seconds later: I will try the same thing again, no matter if the moment is perfect or not
-- he loses the ball
Ball 3, 60 seconds later: I will try the same thing again, no matter what
-- he makes a good pass this time
= then people jump and say: But he is so brave, no one else is brave enough to try things which he is doing.
Total: 3 minutes, 2 lost balls, 1 good pass.
Without him: we would keep the ball for 3 minutes and eventually create a clear chance since opponents will always eventually lose the concentration.
A guy has lately turned into an action-killer.
When the ball gets to Neymar, he will try something complicated and we will either get:
1) a lost ball
2) a perfect pass
But again, he is totally killing a buildup, possession game, waiting for a perfect moment to execute a pass, etc.
To some extent, people are saying that our midfield doesn't control matches anymore.
My estimation is: if you remove Neymar from a starting 11 and put, for example Arda:
= we will play a controlled football then
Arda will make less key through balls, but also, he will lose less balls for no reason, and thus our team will keep the possession, pass the ball around and eventually Messi, Rakitic, Iniesta, Arda or Suarez will make a key pass in a moment when there will be opportunity for a killer pass and that's it.
Neymar is creating some good things, but he is losing so many balls (16 against Monchengladbach) and imo, he is totally killing our flow lately.
I am looking forward to a match when Neymar won't play, just to see whether our starting 11 will have way more possession and control when he won't be on a field.
That's exactly it. Ney often takes riskier attempts and unorthodox moves that leave the opposition flat-footed. He's creative in that way. The riskier it is, the greater the odds of missing but when it works, it's magic! That's why chastising him for low completed passes % is a bit unfair 
