Backstab.
I don't mind that. It might be a little high, but you telegraph that move. It's avoidable. Backstab is nearly instant, they teleport behind you - or are invisible when they use it, and there is no way to avoid it. As an elementalist guarding or capping a point - I can be killed before it's possible for me to respond. I think that's a bit of an issue.
Axe has a required buildup(You have to wack at things for a while), is bright shiny, and has a 2 second charge prior to it, and is relativly easy to dodge(I only got hit by it once before I knew to roll when warriors rear back). Backstab has no buildup, they can use it every 3 seconds(stealth debuff), and is impossible to avoid.