Well we had some small ideas on how to balance it both out, we were thinking of maybe introducing OSRS items as upgrades to pre-eoc items
Such as using a trident of the seas on a polypore staff and hope it upgrades with a % chance, which will slightly boost the magic bonus for example on the staff maybe like +10-15 or even possibly adding an additional 5% damage boost which if your 99 magic and have all % magic damage dealing items you would be hitting over 33s with polypore if i remember correctly. This is just something we are thinking about doing, we are looking for other alternatives, like maybe hand editing every item to make it relevant like a warrior ring/berserker ring type of thing for these items so one would be better in accuracy in defense and other would be better in boosting your damage. All in all we are not in beta yet and its up to the players to decide what will work and what will not we got some great ideas and we hope you will enjoy Onyx!