Alarak is very intentionally similar to Artanis. Possibly the most notable similarity is that their attack damage is identical - they're both using psi blades, although different types - but Alarak relies less on abilities and more on his high attack speed to deal damage.
Deadly Charge is an excellent gap-closer on a short cooldown, which has the benefit of also dealing damage.
Destruction Wave is a good way to push away enemies who get too close, or, even better, to push enemies back into range of your cannons early on, if you manage to get behind them.
Terrazine Slash adds a bit more damage but more importantly adds a slow.
Thermal Lance is sort of like Valla's Vengeance, except only one wave and minus the stun. Okay, it's like Falstad's Hinterland Blast. ...Except without the charging-up time.
Solar Bombardment is a little bit weird for Alarak but it provides an extra level of similarity to Artanis -- they both have global abilities that allow them to impact the battle from anywhere.
Artanis is very much a commander and a supportive damage-dealing tank. Alarak is just a damage-dealer. He's similar to Artanis in a lot of ways, and can in fact absorb tons of damage if he's in a teamfight that he's winning (I'll get to his trait in a moment), but his primary power is in rushing to enemies, slicing them a lot, zapping them with orbs, and throwing them into the air.
Now, his trait... Soul Absorption. This is a huge deal in the late-game and in teamfights, and also gives him even more duel power. Basically, if he fights an enemy and barely defeats them, this heals him for about half his health, so he's ready for more. As long as Alarak is winning fights, this trait means he can win them relentlessly -- which very much fits my idea of Alarak as a hero. Soul Absorption can be countered simply by not letting Alarak take down any heroes.
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Heroes of the Storm Build Guides
I Like this concept and would play it if Blizzard went on this site and took suggestions