Obviously he's not the player he used to be anymore, he has lost his pace and his quick feet. His pace has been gone for years now, that's not really a surprise, it's his general stiffness that is relatively new and means the end of his career is near. But that doesn't mean he can't be a very useful striker this season. He will miss chances but he will also make chances out of situations that can't be considered a chance with a different striker. We can pretend he's been wasteful in an otherwise well performing squad that created a lot of chances, but I don't think that's the case.
He should be used right, as a static striker. That means that he needs dynamic players around him who make runs with conviction, not reacting to a flick but acting before it comes, or not. To make a static striker work you need more of a plan than with a different type of striker.