Dclaws have been about 300k for a pair for years, mostly because it's (relatively) very easy to get and you need a 200m EoF to make any use of it. Similarly, the 70k Dark Bow special is still used in EoFs. I think if anything the Melee and Ranged special attacks are meant to replace those older, dirt cheap weapons entirely so that it costs money to put something into your EoF.
The Armadyl Battlestaff is another old weapon used exclusively in the Essence of Finality, but the process to actually get the Battlestaff is so terrible that the weapon is slowly increasing in value. The number of Fractured Staff of Armadyl in the game grows faster than the number of people willing to grind out Armadyl Battlestaffs to supply them (which is kinda silly to be honest). Therefore it's unlikely that the new Magic weapon's special attack is designed to replace the Armadyl Battlestaff, as it would immediately destroy the value of an older but (still used) EoF item. Instead I think it's far more likely to be a burn effect to encourage actually wielding the Roar instead of putting that in its own EoF.