It would be silly not to go for ES when playing with a Lit-Soso, except if ya plan on making a sorc with as much dmg as possible. With Lit-skillers and your other equipment you get your ES nicely boosted 'free of charge', and not to take advantage of this wouldn't be that wise of a decision.
mhl12, mentioned that in PvP if ya get Charged upon you'd loose your manapool and thus not being able to flee using teleport. I duel with a Lit-soso and from my personal experience I can say that this is so not true. One should keep in mind that a decent Lit-Soso's teleport costs only 1-mana to cast.