If we aren't going to accept some years of non-contention (which is perfectly understandable), I think it's long past time to take the swing at a guy like Marner. Of course, I believe it's even odds (maybe better) that Marner's "playoff woes" are overblown and/or due for a progression to his mean play, so that makes the move more palatable to me.
That of course doesn't mean that we'll actually get Marner since other teams will likely be involved, and we don't even know if he'd waive to come here, but star players in their prime come around only so often.