Originally Posted by
ty_taurus
That's what I've been saying.
The trick is not relying on % boosts to the target's damage, or stats like critical hit. It's creating flat potency damage that technically comes from the caster, but is executed by the target, and to make the job functional in solo, that target can also be the caster. I've beaten my engine building concept to death, but how about a slightly different example.
What if Astro had a spell that summons six stars around the target of the spell. Each time that target attacks an enemy, a star is consumed to deal a 100 potency attack that technically comes from you; this can occur once per 3 seconds. You can only apply this buff on 3 characters at a time. Something like that would make a lot of your GCD gameplay build around targeting other players instead of enemies, and you could try and build on that concept more. Because replacing Malefic spam with this doesn't fix the problem, it just redirects it, so you'd want some other support to give more variety to your gameplay, but that could be a place to start.