First time I've heard of copyright trolls, so it's worth unpacking that..

If you knowingly reuse a work, then I'd argue they are not a troll, they are a copyright holder, so go figure out a license fee.

What about unknowingly using something they claim? That's more subtle, and I buy the argument there. Copyright expiry would help to avoid nonsense claims. But maybe sane courts can adjudicate that - then again Sane Courts (laughing).

But aiming overall copyright expiry to limit nonsense claims, would also prejudice real works that need real protection. So do we lose more than we gain?

So assuming expiring is good - lifetime of author plus a bit?