Conc blast is going to be nerfed to hell with the combat updates coming soon, with Sonic Wave being better on anything where you have a chance of missing, for slayer I think Seismics might still be okay, but pretty much every basic ability is crap, so I can see lazy-mode slayers (read: Revolution users) having a huge drop in XP rates. I'll make a video of the easiest way to kill Kalgerion Demons with mage, it does require seismics, but you get really really fast kills, and can live off soul split if you know what you're doing, so I can imagine the slayer rate being way higher with Slayer Helm's accuracy boost.