in ranked the much higher dmg that madness does in 8v8 wz will be lower (it will normally still be higher than lightning) but since there are fewer persons to which your dots spread in a 4v4 ranked, the dmg difference will be lower.
while i still would go with madness for pvp everytime, lightning has better burst. lightning also has some group utility (for example extra stun on chain lightning etc, but madness has utility too, for example slow on dots) and as you already said, you are a bit more mobile but you lack madnesses self heal.
the main problem of madness is that you can purge the dots, and some classes like jugg (which can get healed by your dots) or oper (which will have his evasion on cooldown every 20secs cause of your dot ticks) actually benefit from you hitting them (which does not happen with lightning).
the main upside i find in lightning is that if you fight against it, the animations just look super beautiful when they hit you. There literally is no beautifuller way to die in swtor, then getting killed by a lightning sorc. (but tbh that does not happen very often).
if i were you, i would just stick with what i enjoy most. and if that is lightning/telekinesis, then i would roll with that.