My suggestion is to buff the dagannoth rings (Berserker, Archer, Seers', Warrior) rings and to nerf the Ring of Stone & Ring of Vigour.
The idea behind this is to implement more diversity between our gear. I find the idea of having a single ring being the "best ring" easy.
Easy as in, you can own a single item to have the best stats out of that gear slot.
Using these rings would force us to use more items in-game, leading to a bigger use of the game content, without leaving it to the abysses.
Being similar to the "Attack bonus"... Melee used to have a wider range of stats, being Stab, Slash and Crush. Having these forced us to use different gear in different situations, may they be PvM or PvP.
Feel free to share your thoughts