Im sure this will have been mentioned before but I cant locate a post discussing it, so if you dont ask you dont get right?
The skip and block feature is brilliant, so is the extend, but I think a preferred list of maybe a maximum of three would be beneficial for new players (granted there arent many so maybe this is a slightly selfish request)
It would allow you to prioritise either a) stat gains, via preferring tasks of a nice that gives good exp or b) financial gains, an npc that potentially drops more valuable loot.
An example of this would be, at -70 slayer i would set a preference of sand burrowers as the exp gain and financial gain is greater than say, pack leader tasks, which i seem to get often haha.
Just a thought.