10% Slashing Resistance IS totally useless compared to even 5% damage reduction. We are here to tank and take less damage not do more damage. The increase damage is no longer current with the new IB change leech from 300% to 100% and I'd say this 50% Leech with damage reduction at 60 TP? Why the hell wouldn't you use it? And unless SE gets a bump up to 24 seconds the benefit is too short to even warrant it being in rotation.
5% is cutting it low, they might even put it at -10% Damage reduction which applies to both magic and physical making it stronger than Rage of Halone debuff. even considering the lowest debuff time of 10-12s though I do believe they will make it 20s. This literally destroys SE utility unless you want the -50% healing which will make SE into a Warrior PvP-esque skill.