Yeah, 2h weapons are great only for crowds.
Here are few practical uses for stagbreaker or iron sledge:
Skellies raid - just gather them on one place and smash them (i love to bully them with stagbreaker)
Wolves raid - hop on a stone and smash them.
Sunken crypts - before you enter a new room with a drauger spawner and/or blobs, dont clear the whole muddy scrap pile. Clear enough to come in range and kill all draugrs, blobs and spawner with stagbreaker without giving them a chance to attack you.