It's not even close, swords is basically = a 1% dps gain per pt in the talent and it scales incredibly well with raid buffs, while lethality is at best a .5% increase unless your crit % is 35%ish. And if you don't have swords atm go 5/5 in deadliness rather than lethality, lethality is one of the worst per talent pt dps modifiers.