I agree both have played well recently, but disagree with the OP's arguments. I don't think either player is consistent, thus hoping they are the key is perhaps a dangerous proposition.
Kolarov was great last week, but lets be honest hear, that is not the average Kolarov. That is Kolarov having a blinder. And that happens to everyone sometimes. The key is to figure out what the average expectations are, based on how well they have played on average. Kolarov has been below par in most games.
Both defensively and offensively. I know the great game last week has got many proclaiming his superior offensive input vis a vis Clichy. But this is a fallacy. He makes so many mistakes offensively, and gives up possession (something we cherish in our style) way more often than Clichy does. His crosses, which were amazing this weekend, have over the course of the season, been inferior to Clichy's. Who himself isn't a great crosser.
Yes, he can whip a mean cross, and yes he can hit a mean shot. But his consistency is atrocious at both. Lets not confuse the beauty of his best efforts, for his mode efforts. Without knowing who is hot or not in practice (seeing as I am not there) based on performances in the shirt, I'd always pick Clichy unless he has played midweek or is nursing an injury. He is just a superior footballer to Kolarov. PERIOD!
As for AJ, yes he can beat a man, but often to no avail. He doesn't cross much, and his style suggests he wouldn't even if he were on the left. He just doesn't play the whip the ball in style, no matter the wing. I have seen a host of players playing on the inverted wing and still whip in mean balls after a switch to the superior foot. AJ's just doesn't do this. And worse still of all our players who play wide, he is the worst at feeding a FB who overlaps him. Can't count how many times he wasted Zaba as an option last week. Zaba was frustrated on one of the misses. He just diddles on the ball too long, and takes too long to see the play.
He too, cannot be key to our success.
However, I agree with the OP's overall assessment that an improvement in stretching the field wide will be key to us winning the league. I do however disagree on the personnel choices to achieve this end.
In my opinion, Yaya switching field like a pendulum, and Pizzzaro's searching pass to an overlapping FB in stride are the real keys. get the ball to an open and wide fullback and you are likely to see more crosses into the box, and more Dzeko, Balo and Aguero attacking the goal area.
The key isn't the crosser, but the guys who are able to find the crossers early and often.