"Scaling" is how much your DPS increases with stats. It's an issue when your class starts our strong, and falls way down the charts as people gear up, or you start low and fall further and further behind relative to the pack as time goes on. That's not really the case with Shaman specs; Enhancement's been fine, Resto's apparent scaling issues are ENTIRELY due to how their Mastery works and is affected by increased gear levels on the rest of the raid group and healers, and Elemental started low and held place; Elemental's issue is that they're just tuned too low, not that scaling is giving them an issue.