The ripped/broken/old items are upgraded with crafting. If you manage to HQ them they are solid pieces of gear for the level of the item.
As for cross-class, PLD has a bit of healing potency 202 vs 131 on my DRG, basically this is the only boost to cure we get. It's not worth using in battle, if you need an emergency cure try and get someone to craft up some mega-potions for you.