Personally, I'd use skeletons instead of boneshards. The skeletons control PC movement whilst the wight darts in and around the PC's, but neither is too hard to take out after having burned through dailies in the previous encounter. It's an 'about right' encounter for 1st-level.
Either that, or change the text to read that the encounter takes place after they have had a chance to extended rest so that the can have levelled to 2nd, or at least be fully refreshed, before taking on the encounter.
Either that, or change the text to read that the encounter takes place after they have had a chance to extended rest so that the can have levelled to 2nd, or at least be fully refreshed, before taking on the encounter.