This should be part of the base events system, definitely.
But what would you end up using for the input event arguments?
RegisterInputEvent(fxDTSbrick,"onProjectileHit","Self fxDTSbrick\tPlayer Player\tClient GameConnection\tMinigame MiniGame","{datablock projectiledata} == {Projectile getDatablock()}");
If you're not quite getting that:
RegisterInputEvent(classname, input, targetlist, arguments);
Where the arguments are formatted as:
{selectable value} logic {comparison value} TAB {selectable value} logic {comparison value}
Selectable value is something like an output event parameter, possibly within those, comma-separate for certain things. The comparison value is {input trigger object SPC method or value}.
Another thought would be that if you wanted configurable logic, you would use
{selectable value} {logic list} {comparison value}
ie;
RegisterInputEvent(fxDTSbrick,"onProjectileHit","Self fxDTSbrick\tPlayer Player\tClient GameConnection\tMinigame MiniGame","{datablock projectiledata} {== !=} {Projectile getDatablock()}");
A list of possible logic comparisons, selectable by the user.
Another example:
RegisterInputEvent(fxDTSbrick,"onActivate","Self fxDTSbrick\tPlayer Player\tClient GameConnection\tMinigame MiniGame","{int 0 3} {== != > < >= <=} {Self getTrustLevel(Player)}");
That should be fairly obvious (albeit that I don't remember if fxDTSbrick::getTrustLevel(%obj) is valid).
Also, input trigger objects - like $InputTarget_["targetname"], you use $InputTrigger_["triggername"] - in this instance, $InputTrigger_["Projectile"] is the projectile that hit the brick. Assumedly one would also (in good practice) set $InputTriggers for the four targets as well - or perhaps simply use $InputTarget values instead of another set.
I dunno, it all seems like a decent idea in my mind, but things come out wrong all the time.
Note: After rereading that, I'll leave it there, but add this - the arguments in that way might be a bit too restricted. Perhaps an open format would be possible, with support for and/or systems and the like, but that might be a little... over the top, to say the least.