World Of Warcraft: Channeled Spells Working as Intended

A recent debate on the ability of "beam" or "ray" type spells, such as Drain Life , Mind Flay, and Arcane Missiles, to continue to hit regardless of range or LoS once they've started reached a succinct close today, as Drysc threw down the gauntlet on why they chose to implement this particular feature into the game:

Yes, that's how they're supposed to work.

Generally when attacking you want to be at maximum range, that allows plenty of time between you and the target to get out as many casts as possible. Now for a straight up cast and fly spell, it's cast, it's on it's way, and that's it, it's going to hit. For the channeled spells (I had actually never heard them called "rays" before today, we call the effect a "beam" usually) you cast, and you hold, and that damage can be interrupted or broken. To allow some sort of leeway, some give so that at max range it isn't just instantly wasted all of the time (which would happen, a lot, especially in PvE) it's given a little extra room to grow and follow.

The gist being that without the ability to track past range and LoS, channeled spells would be far too easy to avoid compared to their simpler fire and forget brethren.