You cannot simply make such an assumption. Simply stating that Kravstov and by next year an 18 year old Kakko can immediately step in and be top 6 forwards is setting your self up for possible disappointment. And while Andersson and Chytil can take steps forward, you have no idea of how much.
Seriously.
Let it become a "problem" before assuming it will be one. These things normally sort themselves out.