Divine healing uses same effect as Renewal, and as such doesn't stack. While divine healing is up, if renewal is cast then for duration of renewal divine healing does not keep ticking away.
As an ability that cannot crit, self-healing for 30-95ish in R1 with 810 psp and 210 hamp, the benefits of this seem weak. Also doesn't proc other carry-on effects like primal mantle cocoons, destiny mantle procs and such. Which is a good thing - it'd be op if it did.
The real use-case of this is low difficulty scenarios where you have one main target that benefits from your renewal and several others you stack Divine Healing on, which does make it easier to prevent overtime tick damage from taking people low hp over time. As far as I'm concerned, unless there is a bug that makes it better than expected with other combinations of hings, this is a cosmetic change to a weak ability. This is a raid soloist / afk healer tool now.
The problem with Radiant Servant tree is that it doesn't scale, and the changes implemented were such that do not scale. They're still low difficulty tools. Picture me disappointed.
Edit: radiant servant is still an excellent side tree to go up to t4 on depending on your build - my problem with this is that these changes encourage the afk nature of radiant servant healing and fixed none of the issues.