No that 's not right at all.
Check the rules on Page 67
If the power requires a target you must have LOS. The only powers that can use Fire Points are Witchfires, any other Psychic Power that targets a unit cannot use fire points.
Doom would not be able to be done from a vehicle as it "targets a non-vehicle unit within 24""
This is very strange as none of the Eldar powers ever needed LOS before. I'm looking through the FAQ which used to expclitey say we did not need LOS and cannot find it.
The Eldar, more than any other army, should not only look at the output of each unit individually, but the synergy of multiple units together and their role in the force as a whole. - Fable