Well if you want full control i.e. direct damage, then we’re back to square one: pure ST turret that can’t cleave because Barrage doesn’t play nice with ST dps, and cooldowns won’t really help in the long run. 8s cleave from Touch, 20s cleave from Deathborne, and you’re tank-tier DPS again. Sure, my proposed solution of exploding Blast passive isn’t very tidy or nice, but it doesn’t have to conform to someone’s sense of aesthetics or OCD. It has to WORK, that is: give us some cleave that is NOT on long cooldown. Or, idk, Nether Tempest baseline and tuned so it beats ST rotation on 2-3 targets but AE is better on 4?
…that WORKS VERY WELL DESPITE BEING EZ MODE. And THAT is what matters. They’re easy yet well-performing & have a tool to deal pretty much everything. You know, sort of like old Arcane. The Wrath one. The one that COULD cast ranged AoE spells and, with some talent tinkering, boost them to ridiculous levels of DPS despite in theory being ST turret.
Which sadly is the one thing we know Blizz is the most unlikely to do. As they have proven time and again, unless they’re STRONGLY pressured into behaving semi-decently, they won’t. And even then they will react in some knee-jerk fashion out of pure spite, like that corruption vendor with time-based inventory. Or putting Missiles back on 3-stack, but not putting its proc on “chance on spellcast” mechanics so it’s not of much use.
Edit: Forgot to add that Barrage is so bloody “smart” that it won’t hit ANYTHING that is not in combat with you, even if it WILL be 0,000001s after spell cast. And it selects targets by proximity first, then randomly if there are more targets than spell projectiles. No RNG, eh?