Arteta worked with him at Manchester city, he'll know how to best use him at Arsenal, maybe he's the missing piece to get him the title who knows but all I can say about sterling is, Arteta can definitely get some good games out of him but that won't last, it never does. Highest 1/2 good season but he won't be consistent. I know what we suffered with him at Chelsea. Holds the ball too much and kills attacks. I hope he impove though so we can get rid of him finally.
There's a possibility, they can also take all 3 points too. Although man city are in great form but Brentford has what it takes to cause an upset. Also just as you have said, Pep might want to play more of his second choices in preparation for the champions league. Pep priority has to be the champions league. Winning the league won't excite him that much again as he can win without even trying.