At 18 on my second life I ended up dumping the SD tree altogether to get Greater Heroism and Improved Recovery III from the human tree, then spent the rest on a second +1 strength from Warpriest, the human THF line and +saves from inflame. I'm quite enjoying the heal effect from smite foe while solo, and positively loving it in groups. The only downside is if smite doesn't hit an enemy (like it dies before your swing lands) you get no heal effect.
Divine Healing is certainly an option to consider if you decide to drop the SD tree. It's a bummer losing the 25 PRR and +3 saves, though, so I may switch back to that version once I get back to epics. Right now I just love getting my 36-minute GH clickie, 7 times per rest. Buff the whole party for free!