Set at a fix health rate rather than a %. It only punishes tanks and users with high health to have it % based and you should be hit for a 15k at 15k health just because you choose to not being squishy? seems a little backwards if you ask me. I would suggest making executes in pvp function as a scale from 10k health with the 25% health mark being 7k you get hit with an execute at 7k you're dead pretty straight forward.