Previously it provided full caster level regardless of background as a divine or arcane class, it gave divine grace and later provided you divine shield, divine might, and the ability to turn undead if you did not already have it.
Currently, this is how it works out:

Compared still to the bells and whistles of the other paths it has become a lot more bland with little thematics too or and its mechanical bonuses aren't really that great. If you want to be a divine harper of any type you're better off going Harper Priest as a cleric or a paladin, or doing a bardaddin under Master Harper where your caster levels are unnerfed and you are honestly better than most base class multiclasses.
Even the Harper Scout allows for an untyped +3 Caster Level bonus spread throughout which can be incredibly useful for certain builds, its `improved sneak-attacks' are actually 2d6 free sneaks that stack with all kinds but can even supplement a class which is not taking them.
Harper Paragon even loses the Harper Knowledge feats which are a tiny RP bonus of +5 lore for whatever reason and all the other subclasses maintain it.
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Could this pathway be given a second glance? You can't just re-specialize as a different kind of harper in game and while you can certainly go `hey nothing is forever, things change`, this was one of the more popular harper builds - some people who built around it are probably in a weird, squishy spot.
While I can absolutely appreciate the efforts taken to make the other paths both desirable and capable of fitting to thematics - harper paragon is sort of a corpse now. Free feats and abilities you normally can't take and a +6 UNI save are objectively neat and useful but I don't really think it's enough to justify taking it.
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Some small suggestions I have are:
1) Fix Detect Evil (you can't use it currently), and potentially have to include ANY divine class towards the DC, whether it be paladin, druid, cleric, CoT, or ranger. Maybe include 1/2 class levels for non-divine classes - because otherwise this is just a whistle, and not very useful.
2) Potentially include full CL for Divine Classes (paladin, druid, cleric, ranger) for the caster level bonuses to the class. You're already divine, the gods love and bless you, you should probably reap the benefits and not be made weaker for taking something that is clearly divine themed. The current `every other CL` is probably fine but you could have it follow the Harper Scout and make it +3 which at most makes any sort of DIET BARDADDINS 23+ spell level.
3) Your divine classes should count towards your turning CL. You get turning, but it's rather worthless beyond using it for divine might or divine shield. So druid, paladin, ranger, and cleric levels counting towards your turning level would be nice and thematic, and emphasis that this is a specialized holy warrior rather than a dip.
4) Restore Harper Knowledge, I have no idea why it was even removed. It's not godly powerful. Harpers encourage the sharing of knowledge.
5) Bump up when you get divine might, divine shield, and turning. You have to completely invest in this as an end game sort of thing and are disadvantaged if you take it pre-epic, for those that do that, and for those who take it otherwise it'd be nice to get use of the whole reason you're probably going down this path before you're level 30. I think giving divine might at level 3 / turning at the 3rd level, and divine shield at the fourth would be a nice bonus.
6) Give it the god aspect bonus of the Harper Priest. The harpers as an organization are blessed directly by several different deities, the Entire Elven Pantheon, and many of the deities of knowledge, magic, nature, and good. Given it's also a divine class receiving the different aspects would be a neat, and not overtly mechanical bonus. Useful without making you a demigod and thematic.
7) I suppose at the fifth level it could receive extra turning or planar turning as some sort of extra cookie. Currently its made so you have to invest all the way to the fifth level to "get it all" so to speak. It is otherwise dead water, empty, and without a soul. Which is weird because it's called Harper Paragon.
Compared to the current image of the class, I'd like to see it resemble this:
Level:
1: -detect evil (divine class levels count, non-divine count 1/2 towards DC)
Harper Knowledge
+1 Divine Caster Level
Bonus Feat (Fav Enemy or Curse Song)
+2 Universal Saves
2:
+1 Divine Caster Level
+1 Arcane Caster Level
3:
+1 Divine Caster Level
Turn Undead (Divine Caster Level counts towards Turn Level, 1/2 non-divine)
Divine Might/Shield
+2 Universal Saves
4:
+1 Divine Caster Level
+1 Arcane Caster Level
Divine Shield/Divine Might
5:
+1 Divine Caster Level
Bonus Feat (Fav Enemy or Curse Song)
+2 Universal Saves
Treated as having all six deity aspects
Extra Turning or Planar Turning
that's all folks, hope something is done to make this less bland and more thematic.