As the title states, I feel like these should be class skills for the Druid rather than effectively forcing every one of them to cross-class these skills. It would allow them a little more diversity in their skill selection I think!
Druids already routinely get some of the best stealth scores in the game. Making this change would be technically complicated and require a great deal of re-balancing of items/spells/etc. So I don't think it likely.