I have to disagree with OP. My perspective is less mechanics/balance and more lore based. RTL – skill description begins with “Ride the lightning to your foe”. Lightning being essentially pure energy, would not be influence by physical movement altering effects – e.g. not slowed by cripple or chilled.
In fact, one could make the argument that it should remove the chilled effect – sitting on plasma would leave you a bit chafed and warm, not chilled