That's right, because the combination of senior players is very important in a team. As you said they still need guidance and experience from their senior, because to be a solid team senior role is very important at there, although that young players have talent but if they are not solid it will make it difficult to got a winning.
Still a hot rumor, but it seems like a center forward who deserves to replace Benzema is Kane, because he is very well established in terms of mentality, playing maturity and scoring goals.
it is certain that even though young players have better performance and talent than seniors, they are not experienced enough for several matches such as the champions league or European league, which should indeed be young players need senior players to share experience and guide them to become talented young players for bring his team to perform better.
I agree that if the rumors are true, Harry Kane has almost the same performance as Benzema, which can bring Real Madrid stronger and better this summer.