[Shujin]

As long as CEL, or rather being faster than your opponent, is a disadvantage in the game and its mechanics, skills that are "telegraphed" will always benefit the more reliable tanky version of a user. Unless its something like Setting Sun of course.
the slow ones will be able to react and most of the time be able to avoid the damage entirely. So it being evade-ignore kinda just adds insult to injury.
I really wish CEL/Turn order was actually beneficial to faster people.

litte side rant:
In my topic of "When is it okay to ignore Evade" I pointed Explosion out as well, like 2-3 months ago. The answer I got was "Mimimi, when one skill is countering your build, your build is shit." So I wonder where those smartasses are now. "just use a Red letter" or some other high-quality comments that totally reflect actual balance.

Little rant aside, glad people catch on to how oppressive this skill really is to a whole archetype.
The only thing I sort of want to say is that maybe number/effect tweaking would probably be the better version, unless you really just want a Setting Sun light version?
Don't know if there might be a more interesting tweak with effects in the vein of
"If target has higher Cel than you, XY effect it not working."
or
"If you are faster than your target your skill gains XY effect."

I think those conditional effects could help the issue of CEL being a disadvantage in future. That way a very fast explosion user might still just get the current iteration of Explosion, when he uses it against someone slower. Though its still telegraphed then.
So I don't know, I think Explosion is just one of the telltale things that shows whats wrong with Turn Order, makes me think that explosion isn't the real problem but just an side effect of it.