There are, like, two weapons that deal Pierce/Elem damage, one that does Pierce/Shadow. Are there any that deal Shadow/Elem? If not, I think some of us could really use one, possibly as an excuse to complement the Peacemaker and Sentenza in terms of damage type coverage.
Also, I do notice that where these dual-type damage weapons would sensibly deal normal damage instead deal reduced damage, as if it were ineffective (e.g. Peacemaker does poorly against Constructs as if it only does piercing, even though it's half-elemental). What's up with that?
Because monster resistances are stronger then weaknesses.
As of right now there are no Shadow/Elemental weapons, but it gets talked about frequently.