Well, I was just sitting here leveling, and in terms of class's multi attacks, I IMAGINE it'd be cool if they all had secondary perks.

Pally/Fig spin has fragor chance when they spin
Ranger has exploding arrows
Warlock has poison with it
Darkwar have bigger juxta chance
Druid has nothing but multi is in a good state (fast casting, no mob limit)

Wizard has nothing
Diab/cleric has nothing

My thoughts on how diab/cleric/wizard could be improved are as follows. Nothing overpowered and it wouldn't help in raids/pvp but it would make their PVE a little better.

Diab/cleric: What if their beam had a small chance to fracture and bounce off enemies? Let's say for example your fighting 30 hell knights, and your beam hits 10. There could be a 1 in 30 chance that one of those ten beams would fracture and hit another hellknight so you'd hit 11 instead of 10. This would be RNG based so you may end up fracturing multiple times per cast and hitting 15 of the 30 at times. We've all seen chain lightning bouncing around in other games, so think of this as a spirit magic form of it.

Wizard: Wizard used to have a secondary effect that was a small fragor around their multi, this was just visual, but what if we brought this back with a small tweak? That fragor could do 5% of your multi damage to surrounding mobs (max of 8) like splash damage. In many other games, wizard classes are known for their aoe nuking capabilities and mastery over elements.. so i think minor splash damage would be the least we could do for wizards.

I like this idea, and it helps differentiate the classes abit.

Id like to see cleric and diab given more unique features specifically so that way they are a bit more distinguished from each other. Also on Xen 2 they are the least favored of the casters.

Diab gets innate fire bonus, and disintegrate. So it would be cool to see an expansion upon those in some way. Perhaps a skill that could have a chance to trigger disintegrate on targets? Or a chance at free activating the fire shield mastery skill?

Cleric gets bonus energy damage I believe (can't check notes atm) and critical energy skill. In my suggestion post for x2 I thought chain fulgar would be a neat feature for them, but maybe a chance to trigger fulgar could be neat? Probably abit OP, for pvp but could be balanced somehow. At least disintegrate is a dot vs nuke.

Wizard multi follows it's target off screen, every other spell doesn't.

Yeah I will say Wiz multi does seem to be in a good place for pve on 2.0 at least in the 1 to 30 range. That's why I suggested tweaking cleric and diabolist.