Regardless of your build, elementalist is squishy. Dodging and knowing when to switch attunements is key, along with traiting yourself accordingly.
For example, a lvl 25 scepter/dagger build with 10 in air, 5 in water makes you run much faster while staying in air, great for quick entries and exits in and from the battlefield, and gives you a window of opportunity to use your healing skill if the need arises. And dagger has Ride The Lightning which is both a quick assault that leads into an area attack in fire or earth attunement, and an emergency escape. Likewise, if you cannot switch to air attunement because of cooldown, you have regeneration in water attunement, perfect after a switch from earth attunement which inflicts bleeding. I’ve been going with this build for some time now and plan on traiting mostly in air and focusing on mobility, and it works well.
Staff is great for support and when you’re in the back row. For everything else, choose one of the other combinations.