Good S/D combo?
Try to add Arcane brilliance as your healing skill. It give you 18 might over the 15 you have. Later, there is a trait that give you ferocity boost after you used a arcane skill, so you can alternate you different arcane skill to get the boost for long period of time.
Also, scepter is not that effective as a dmg weapons (except for the burst you talk about). The best effective way to play scepter/dagger is to only use those to stack might and then use Light Hammer as the main source of your dmg. Of course right now, the sceptre is fine for you. Its will burst down most enemies, but latter you will need the LH to get good dmg over a longer period of time.
before you swap to earth you could use fire 5, that can pack a wallop and at the start of the combo might as well use air 2, its instant cast and can be used same time as air 3 or during earth 5’s channel if you swap attunements