I'd say Barkley, Shelvey, Ballotelli and Di Maria back themselves to shoot from distance and frequently try it. Not surprising that Ballotelli is the only striker on there. His shooting last season was appalling.
And it's the same reason it's illogical to expect 10 goals from Coutinho if he doesn't change where he takes his shots from, or have a big jump in accuracy. Here's Coutinho's breakdown last season (league only);
% shots outside the box: 65% (67/103)
Conversion rate : 3.1% ( 2/ 67)
% shots inside the box : 35% (36/103)
Conversion rate : 8.3% ( 3/ 36)
So when Coutinho shapes up to hit a shot, you can roughly predict that his chance of scoring = (0.65 x 0.03 + 0.35 x 0.083) x 100% = 4.8%
One for fantasy football players or nerds like me, I guess.
😉
So anyway, unless he shoots more in the box, or improves his shooting percentages, you're looking at 5 goals in 100, assuming he's consistently inaccurate (should be - I'm guessing he was probably shooting like this or worse in 13/14). It's relatively more difficult to improve conversion rates because lots of factors come into play - the player's technique, the circumstances, luck, the type of chances you get, etc. The easier way is probably to switch the distribution of attempts, or increase the volume of shots in the higher conversion rate area (i.e. get into, and shoot in the box!).
There's a reason why wingers / AMs often find it hard to consistently get 10 or more goals in the league - yes, there are a handful who do so of course, but I think there are probably about fewer than 20 of those since the Premier League. Maybe even fewer than 15.