@Destined, others have said this, but I think your point works the opposite way. It's not the role of the core game to dictate what a mapper does (I mean within reason; it shouldn't help mappers make a completely different game). It's the role of the core game to give options to the mapper to make the map they want. Some may want to also make electric lights & robots disable-able and some may not. Even though I brought it up, I don't have a strong opinion about it though. It'd be a kind of gimmick arrow for special case FMs, not for normal use anyway.
In line with that, I think actually the best way to have it is for a mapper to just rig a normal broadhead arrow with a new model and put an S/R on it that triggers a particle, short circuit sound, and turning off whatever it touches. I mean, I think it's something a mapper could make for their own FM without needing source code support. So there's nothing stopping a mapper from making it now. For that matter, I think a flash arrow could also be made by a mapper, since we already have a function for the flash effect; all the mapper would need to do is have a script or S/R trigger it in the right place when the arrow hits.
I'm switching to a different point which is I think the debate here isn't about whether these novelty arrows should be in the core mod, but whether & how mappers can make their own for their own FMs, and then if any turn out to be wildly popular, we can talk about wider use of them further down the road. And if a mapper doesn't want to go to the effort to make them for an FM, now that we've floated the idea*, that kind of answers the debate by itself.
* Now that we've floated the idea again. I think most players don't appreciate that maybe 99.5% of ideas they have, the team already thought about it and had a 6+ page discussion on it back in 2005~2009 going over all the pros and cons in exhausting detail, and then 15+ years later a player thinks about it, and the whole debate replays itself. XD But sometimes some things are still new.