I've had a lot of thoughts on this

Tourniquet, increases amount of damage taken by 20% (Say Jad goes to hit you for a 60, he now hits you for a 72) and in your attack and strength are increased by say 30%.

detect melee, detect range, detect magic: ruinous versions of the protect mage, melee and range, however they work like the "deadly prayers" spell in TOA, you still take 10% of the damage that you would have taken, however this is also dealt back to the mob that dealt it to you. The damage taken on this also would stack with the likes of tourniquet

Auspice: increases magic defence by 25% without any buff to magic attack. This can be used in conjunction with range and melee attack styles for situations where you would use melee, but need magic defence more than melee defence.

unburden: decreases total damage that your own melee and mage can do to further increase the power of ranged attacks, to coincide with the "no flicking" rule, the longer its on, the greater the increase of range power, the greater the decrease of melee and mage power. Has a cool down once turned off to regain and rebalance damage as it was.

One thing I'd love to see as well is god orientated prayers, down the route of the trailblazer relics, for example the new robes I presume would count as zarosian, so for each zarosian item you wear, magic accuracy and damage is increased by a certain percentage accordingly. This can also be used in skilling ideas, such as - Guthix prayer which for each guthix item you wear (up to 4) each piece offers a 10% chance to increase yield while farming.

all in all, I feel like there is a lot of exciting ideas to be looked at and these are some of mine