Think benteke turning into our main man has dictated the way we play with lambert effectively building a team and style of play suited best to his attributes. Think when or if he goes (although we shouldn't sell and we should try our best to keep him as we moan of non improvement then seem to want to sell one of our best players) the style may change again.
Could be argued Kozak was brought in so the style didn't have to change when or if he goes, however I think that was based on more that if benteke got injured we didn't have to move to a style we hadn't worked on. With more time in the summer to work on it you'd like to think that the style could change.