I will throw my log on the fire in that I am of the opinion that the Whispering Cairn will chew up newbie adventurers and spit them out. Note that when I say newbies, I mean new players -- not new characters played by veteran players.
Although veterans can be expected to pick up on the hints regarding the various traps, newbies cannot be expected to do so. Thus, the newbie are at grave risk of blundering into some mighty nasty traps that certainly can kill them.
Also, the for PCs really to succeed will require a lot of investigation and careful planning before taking action. Veterans (sometimes) do this. Newbies typically don't.
I do think the adventure is very good, but I'd be worried about springing it on new players, for fear of getting them in over their heads.