Destiny 2 Warlock BuildCrowd Control Ice Mage

Iceflare Bolts.

It is the same reason I'm not using Glacial Harvest and stacking on Frost Armor, because then you would have Glacial and Bleak Watcher as Aspects—in that case you're better off playing Prismatic with Devour.

Iceflare Bolts is the linchpin here.

Taking advantage of that, with Wicked Implements exotic trait, and Rimecoat's slow icicles—you will be freezing, breaking them, and Iceflare Bolts will go everywhere.

This is why the Fragments are important too,

Refraction gives Healing Rift energy back on Slowed or Freezed kills.

Durance makes Slow, Freeze, and Bleak Watcher last longer.

Shards gives back Grenade energy when you shoot the crystals that pop up near Rimecoat's Bleak Watcher, or Wicked Implement's Catalyst precision kills.

And Rending makes sure that Wicked Implement hits frozen enemies harder so that they shatter and spread Iceflare Bolts, which you can chain freeze the same enemy (or others) over and over when Wicked Implement's "Creeping Attrition" is active inside the Bleak Watcher storm.

Landing 3 precision hits within 4.5 seconds of each other grants the weapon a buff called "Creeping Attrition." The precision hits doesn't have to be the same enemy, it can be a group of minor enemies.

When Creeping Attrition is on, precision hit will Slow enemy. Which will fit well with Rimecoat, because your icicles inside the Bleak Watcher storm slows too.

Slows turn into Freeze. Break the freeze with bonus damage from Wicked Implement -> Iceflare chains freezes.

If you don't feel like you need the Super, you can swap out Dynamo for Special Ammo Finder to be topped up on Special Ammo, if you have a Bait and Switch Heavy weapon.

Or you could have a special finisher.

Why I chose Font of Restoration and Time Dilation is because I have 100 Resilience and Discipline with 70 Recovery. Font of Restoration gives me +30 Recovery, which equals to 100 Recovery.

Recovery stat on Warlock is tied to Rift regen.

Harmonice Loader makes Wicked Implement feel snappy, and Stasis Weapon Surge is nice for VS Chill Inhibitor.

This is a personal preference for me, and anything can be swapped out if seen fit.

However, I have felt that Bolstering Detonation works with Bleak Watcher. Meaning hits with Bleak Watcher gives you back Rift energy.