Beronath’s Fury from the Shard of Beronath component will be better than Troll’s Rage for an Elemental Spellbreaker.
As for a second class, Demolitionist, Shaman and Nightblade are all strong and bring different things to the table. Look at their skills and decide for yourself what you want to do. I’de start by deciding whether you want to go DW or 2H and go from there.
A caster offhand won’t help a ton for a melee build and shield isn’t as strong without the Soldier passives/Devotions but some people still use a 1H/Shield on weapon swap for safety/recovery.