While I understand why, I don't think it really has a major impact on sustainable multi-target (e.g. Iron Maidens), and only a minor impact on "short-term" Multi-Target. You lose some hardcasts that could have been fillers. I don't disagree that the mechanic not shifting to the next recent instance of the DOT is good, but I'm not really persuaded it's a major damage loss that we'd consider Euphoria to take its place.
Considering the major loss would come from things like having Adds die at the transition point, and losing your Moonfire refresh--the boss's MF won't proc SS--and therefore losing out on a few empowered casts (maybe 1 or 2 procs). I can see the argument here, but it's also avoidable.