At a minimum, you need to swap Exalted Soul for something else. You can upkeep your mantra every 3 seconds and activate all your other skills when needed without Exalted Soul. If you're dying too much during melee, try Resolve or The Guardian's Path; if you want to use your cool-down skills and potions more often, try Beacon of Ytar; if you're just dying occasionally, but you feel you could win the fight if you could just hold on a shade longer, try Near Death Experience.
LS is probably the right approach for you. If you swapped an emerald for an amethyst, you'd drop your EDPS by 15% but only increase your sustain by 10%. Unless you're going to look for a new amulet or a different OH weapon, I suppose, your options are limited.
One option to consider is trading Blazing Wrath for something else. If you're spamming Overawe, you're not getting the full benefit of BW's 15% buff because it stacks with Overawe. In your case, it's worth only 10%. Dropping this would lower your EDPS, of course, which would, in turn, lower your sustain. Not by much, mind you, but by a little. (You also lose BW's periodic heal, but this isn't a big deal.) I suggest trying Dashing Strike or Tempest Rush for the added utility, the ability to dictate combat, and the ability to get out of a jam. Dashing Strike takes more time to master but is potentially the better of the two; that said, Tempest Rush has its moments, too. Suggested runes:
DS: Quicksilver (lower spirit cost) or Blinding Speed (20% chance to dodge for 3 seconds)
TR: Slipstream (-25% damage while channeling)