They're Coming

Potential system was way after dual bladers. If I remember correctly, major patches went like this in kMS: Golden temple -> dual bladers -> hob king pq -> 7th anniversary -> potential system/chaos bosses.

Edit:
2/25: Dual bladers
3/31: Hob king pq
4/27: 7th anniversary
5/13: Potential system, follow command, chaos bosses
5/28: Artifact event
6/09: World cup event

There's still quite a long way to go, at least two and a half months, especially if hob king pq doesn't come next patch, which it probably won't.

You guys still need Ghost Ship in the Sea Mist as well.

Is there any benefit to your existing characters from having the Dual Blade on the same account, like the in-account-tradable equips from Aran and Evan, or some new form of Blessing?
(Obviously if you put the DB on another account, it will miss out on those account-locked equips and the Blessing from your main, but I'm asking about the other direction).

They give no account-shareable or karma-able equips. They get their own face accessories but they cannot be moved to any other character. Of course, Nexon could change it like they did for the Dragon Glasses.