Is your feature request related to a problem? Please describe.
I know it doesn't technically belong there but there are some instances of the game that blizzard decided using Unit events instead of combatlog events would be a good Idea. This means that on some bosses in LegionDungeons for example UNIT_SPELLCAST_SUCCESS fires but not start or a normal combatlog event. This means you have to write a simple yet anoying custom trigger everytime.

Describe the solution you'd like
a default trigger to listen for UNIT_SPELLCAST_SUCCEEDED like the combatlog trigger

Describe alternatives you've considered
writing a tsu or custom trigger every time

UNIT_SPELLCAST_SUCCEEDED

function(s,waevent,unit, castGUID, spellID)
if spellID == 198024 then
s[""] = {
duration = 10,
expirationTime = GetTime()+10,
progressType = "timed",
autoHide = true,
changed = true,
show = true,
}
return true
end
end

Additional context

Not as addition to the combat log event trigger, but as a separate trigger.

And yeah I can add that, since it makes your life easier.