Before the enhancement update both Paladin and Ranger had the option for 80 devotion in their class enhancement trees with no requirements. After the update Paladins can only acquire devotion from the Sacred Defender tree and only as many points are spent. The Sacred Defender tree was changed to mostly only function with shields leaving DPS Paladins without any devotion. Now you are doing the same thing to Ranger by forcing most of the devotion into Core DWS abilities. On my melee Tempest ranger I do not have the points to spend in DWS period.
If the change was made to keep 1 or 2 Ranger splash from having too many benefits then simply add devotion to the tier 3/4 Stat in each Ranger AND Paladin tree. This would mean that you would need to splash 3 or 4 levels of Paladin/Ranger and spend a minimum of 12 points in a tree to get 40 devotion with 22 points required for the full 80. Stating that the heal skill is there to make up the different in devotion is not plausible since Paladins are a 2 skill point per level class.