Paladin Parnell plays a bit too much like Caira but with better self sustain. Allow me to make 2 suggestions to make him more distinct.
Shrink the blast radius of his healing rockets, and possibly remove his ability to heal himself using rockets (by shooting his feet). In exchange boost the healing of each rocket slightly so that he heals more damage per rocket hit.
This will give PP a higher skill ceiling and make him distinct from Caira.