I think there is no question that we have been wasteful at times with the chances we create, and the away leg is was clear evidence of that. Additionally if we took more of the chances we created we might be better off not just in this competition but in all competitions. However, not sure I'd grumble that only one of our goals came from open play (just last week there were complaints we don't score enough from set plays on here). Fact is if the opposition deny us good chances by fouling, then us capitalizing on the subsequent free kick is just as much a sign of good attacking play as anything else. Think about the number of cynical yellows WBA pick up before they stole their goal and the 3 points. Credit to them, but it was a classic smash and grab: prevent your opponent from scoring by any means, and hope to nick a goal and the points.
I do agree with you that with Sturridge available for all games and someone else (you know it could be a fit Borini who actually lives up to expectations next season) we could increase our scoring to chances percentage. But I think we do need to focus on the back this summer. Of course we are going to need to replace Carra, but for me we need to ring out the mistakes that have cost us this season.
A few extra goals here or there might have turned some of those matches where we did not get the full points into victories, but as Jason has pointed out on a couple posts, relative to other clubs we're actually not doing that bad on that front (4th highest goal tally in the league), but conceding has been our weakness. Think about both the home and away fixtures against City and I think you'll see where I'm coming from.