@OP
Although I'm sure you have - it is insanely important that you reevaluate your old spells in light of huge, sweeping changes in mana efficiency and HPS. All classes got their quick heals nerfed to all hell, and are expected to switch between extremely low HPS/high HPM spells to mid HPS/mid HPM spells depending on the situation.
The real thing that everyone needs to pay attention to - but that the healer will pick up on the fastest - is damage sources. There are dozens and dozens of odd damage sources that will straight rip your group up.
Queue music -- Damage reflections, buffs that explode, debuffs that explode, debuffs that reduce healing, debuffs that reduce casting speed, ground buffs that reverse damage, ground buffs that heal, ground buffs that deal damage, stacking damage modifiers, swapping damage modifiers, damage modifiers that seem to randomly switch who they're effecting, reverse damage reflections, wind up spells that do hundreds of thousands of damage, instant spells that do hundreds of thousands of damage, buffs that explode when the monster dies, debuffs that explode when the player dies, buffs that do pulse AoEs, buffs that do buffs, buffs that do debuffs, debuffs that do buffs, debuffs that do debuffs, and about a hundred others to add to the comically long list.
These spells happen in trash just as much as they happen in bosses. Learning the damage sources to your group can help SO much! It helps to know which monsters to CC, which to kill first, which to interrupt, which to dispell, and which debuffs on your own group are worth the time and mana to dispell. This can really only happen by going back over the combat logs when you wipe, and paying attention. It just takes time.