No, this isn't ability order combos. This is abilities having extra effects based on other abilities on the same bar.
Such as: Templar Aura + Psijic Meditate: Cast Aura, while aura is active you can channel meditate to heal and restore resources to nearby allies. Probably about 15% of the value meditate targets self with. Base meditate is 1200, 15% would be roughly 180. Ok that's utterly useless. If they add it they'll figure out how to balance it.

Or perhaps some new weapon sets or guild sets, ones that are like weapon sets and acquired similarly to weapon sets but effect guild skills. Particularly Meditate, letting it restore nearby allies, probably 5/8/12m radius. Again, balancing. I'm not the best at it but I can try to make suggestions.

More class sets that effect certain skills, similar to weapon sets. Like changing Aura into a toggle or always active, since it's free cast. Wouldn't affect the soul eater morph though. Or would it? Hmm. I wonder how'd they do that if it does effect that. Automatically eat all souls nearby?

This could be for the free skills and useless skills.
Do any other classes have free skills? Excluding soul eating.

Perhaps another set that increases your speed by 5% per movement skill slotted. Naturally people wouldn't want to have more than one slotted at a time since they all pretty much do the same thing, but the rare person could use that to hit the speed cap, but be utterly useless for everything.