Signing someone like Ehlers, closing in on 30, to an eight year deal makes very little sense for the Isles or for him. Realistically, he will be pretty good for the first 3-4 years of that deal and then the contract will weight you down for the rest of the remaining years. This might work well for a team that feels close to winning the cup, like COL or CAR but maybe not quite being good enough right now. The Isles are years away, and if Ehlers wants to win, he would not choose to come to us.
I'd stay well clear of top free agents, but look for bargains on cheap and short deals instead.