Blade Barrier spam your way to 20. Take just about everything that looks good in Divine Disciple/continue to max WIS and you will be fine. Spell selection shouldn't be an issue since you pretty much get all of them. I only put enough points in radiant servant to unlock positive energy burst. Stuff from the human tree shouldn't be necessary, besides +1 to Wisdom and spellpower boost if you want it.

No idea what your feats are, but as long as you have something like this you should be fine:

Empower Healing, Empower Spell, Heighten Spell, Maximize Spell, Quicken Spell, Spell Focus - Evocation/
Greater Spell Focus - Evocation, Mental Toughness\Improved Mental Toughness.

Toughness is no longer a "required" feat, as you get bonus HP as you hit certain levels (every 5, i think) and it's no longer a pre-requisite for HP from action points.

Swap that shit out.

You could swap that out too for evo\improved mental toughness. Honestly it shouldn't matter, they've changed the exp curve so heroic TR is like easy mode now imo. You should be fine.