The Reaper Assignments are not bad, but they could do with some updates to make it better and here are some of my ideas:
1. Ban List (completionist cape requirement):
Everyone has his/her's favourite task but everyone also got his/her's least favourite tasks (Barrows/Legions/Fight Kiln for me) that we would rather not bother with. My idea was you start with 1 ban and with every 100 reaper points you can buy another ban with a maximum of 3 bans.
2. Reaper Helmet (Upgraded slayer helmet) (completionist cape requirement):
With 300 reaper points you can upgrade your mighty slayer helmet to a Reaper Helmet. This reaper helmet will give you a 5% increased slayer experience on every monster kill (like how the enchanted yaktwee stick works for hunter) and it will allow the slayer helmet passive effect to also work on reaper assignments unless it's already a slayer task (dagannoth kings, qbd, kree'arra etc).
3. A few new pets (500 reaper points per pet)
- Zombie Green/Blue/Red/Black/Bronze/Iron/Steel or Mithril dragon hatchling.
- Zombie Dagannoth
- Lil' Zombie