Would an Electric move be the best option for the second attacking move?
Also, why isn't Psychic used on Latias?
Yes, Electric is a good secondary typing.
Dragon, as Latias' primary STAB, is only resisted by Steel types, which Psychic does absolutely squat about. Along with that, Darks are completely immune and Poison/Fighting coverage isn't exactly the greatest.
So basically, Psychic isn't used on Latias for the reason it's not used on most other Pokemon.
Also (2),is CM Latias better usedin Ubers, OU or both?
Also (3), SpcesLatias Draco Meteor/Ice Beam/TB/Psychic?
Also (4), will Soul Dew even be premitted in OU?
Also (5), will Latios ever go OU? Heatran has the same SpA stat and Overheat, what makes Draco Meteor broken?
Bleh blast. XD I'll do my best.
(2) CM Latias does well in OU, but I have no experience with Ubers. I would guess that it performs pretty well there, too.
(3) I would go with Draco Meteor, Thunderbolt, Surf, and something besides Ice Beam and Psychic. Ice Beam is as redundant as before, and Psychic is as unreliable as before. It's even worse when a Tyranitar can switch in scotch-free and start Dragon Dancing and Pursuit as you switch out.
(4) Probably not. As a free Calm Mind, physical attacks would basically be the only hope of defeating one.
(5) I really can't say for sure on that one, but Latios has a pretty high base speed and decent typing for switching in. As mentioned before, Dragon-type attacks are good to throw around because Steels are the only resists. Latios has the movepool and stats to break through Steels with powerful neutral moves, whereas Heatran will have dificulty countering the waters, rocks, and dragons that usually like to come in on his Fire STABS.