Little Cup stuff is unknown to me, but feel free to post your Little Cup thoughts!
LightningRod has a new perk with it: Whenever the Pokemon absorbs an Electric-type attack, its Special Attack is boosted by one stage and it seems that it doesn't damage the ability-wielder (so yeah LightningRod Seaking isn't THAT much of a joke). New Pokemon that has it? Only one.
Name: Zebraika
Type: Electric
Base Stats: 75 HP | 100 Atk | 63 Def | 80 SpA | 63 SpD | 116 Spe
Notable Movepool known so far: Pursuit, Spark, Discharge, Agility, Thunderbolt, Thunder, Charge Beam, Hidden Power
Zebraika is already a fast Pokemon, so the lost of Motor Drive isn't as huge as it would be for Electivire. 116 Speed dominates Starmie, which is pretty awesome. Anyway, boosting its modest Special Attack is a great idea since Zebraika won't always have a chance to boost its Special Attack with Charge Beam (but it is an option!). It's actually a decent check for Starmie: Note that it has Pursuit in its movepool!
Sadly, Zebraika is the only new Pokemon that gets LightningRod naturally without access to Dream World. Let's look through the Old Pokemon though to see if it impacts anything. First, let's look through non-Dream World Candidates that are notable.
Manectric
Base Stats: 70 HP | 75 Atk | 60 Def | 105 SpA | 60 SpD | 105 Spe
Notable Moves: Thunderbolt, Thunder, Discharge, Overheat, Flamethrower, Charge Beam, Switcheroo, Crunch, Fire Fang, Ice Fang, Thunder Fang, Signal Beam, Hidden Power, Howl
Manectric was a cool Electric-type already. Fire-type attack, Charge Beam to boost its Special Attack, Switcheroo, and a decent move to get around Rotom in UU thanks to Crunch. Seems like an awesome buff. If Choice Specs still exists in Gen 5, Switcheroo Specs is very viable when you consider the possibility of +2 SpA Thunderbolts.
Dream World
Notable Candidates taken in briefing:
Pikachu
Base Stats: 35 HP | 55 Atk | 30 Def | 50 SpA | 40 SpD | 90 Spe
Don't laugh. Yet. Light Ball just makes it insane on the Special Attack spectrum. Now it suddenly just got a little more deadly with the ability. Furthermore, it still retains Grass Knot, so don't think your silly Ground-types will work. Pikachu shall aim for the horn and not miss Rhydon! It is still a glass cannon, but one that can possibly pack a huge wallop. I wouldn't want to be a Pokemon that doesn't resist Electric and takes +3 Thundebolts. Well, maybe Blissey.
Raichu
Base Stats: 60 HP | 90 Atk | 55 Def | 90 SpA | 80 SpD | 100 Spe
Raichu is only noted because it is a sturdier version of Pikachu. Slightly faster too. Granted that Light Ball doesn't work on Raichu, but its moderate bulk helps. Just hope there isn't a faster Pokemon in the fray. Still, Raichu getting a buff is nice to have. Even if it is somewhat inferior to Pikachu. Being able to pull an Encore easier on slower Thunderbolt users is pretty cool.
Zapdos
Base Stats: 90 HP | 90 Atk | 85 Def | 125 SpA | 90 Def | 100 Spe
Technically, the Star of The Show<tm> for LightningRod is Zapods.
Pressure is a cool concept for Defensive Zapdos. Since it still has access to Roost, Zapdos just became MUCH more dangerous offensively. Hell, it even learns Agility and Charge Beam to add insult to the injury. Being a quick Pokemon as is, the only weaknesses it has is that it needs Hidden Power to bust through some of the Ground-types and possible lack of Shadow Ball, Extrasensory, Baton Pass, and Heat Wave. Still, consider that Zapdos was already deadly beast, LightningRod just made it scale higher of an offensive threat. Zapdos getting Lightningrod was a nice buff overall.
Finally, Lightningrod is very viable for Doubles and Triples battles. Sadly, not a very big expert on this one either, but Zapdos gets a huge mention for its resist of Earthquake.
Discuss.
LightningRod has a new perk with it: Whenever the Pokemon absorbs an Electric-type attack, its Special Attack is boosted by one stage and it seems that it doesn't damage the ability-wielder (so yeah LightningRod Seaking isn't THAT much of a joke). New Pokemon that has it? Only one.

Name: Zebraika
Type: Electric
Base Stats: 75 HP | 100 Atk | 63 Def | 80 SpA | 63 SpD | 116 Spe
Notable Movepool known so far: Pursuit, Spark, Discharge, Agility, Thunderbolt, Thunder, Charge Beam, Hidden Power
Zebraika is already a fast Pokemon, so the lost of Motor Drive isn't as huge as it would be for Electivire. 116 Speed dominates Starmie, which is pretty awesome. Anyway, boosting its modest Special Attack is a great idea since Zebraika won't always have a chance to boost its Special Attack with Charge Beam (but it is an option!). It's actually a decent check for Starmie: Note that it has Pursuit in its movepool!
Sadly, Zebraika is the only new Pokemon that gets LightningRod naturally without access to Dream World. Let's look through the Old Pokemon though to see if it impacts anything. First, let's look through non-Dream World Candidates that are notable.

Manectric
Base Stats: 70 HP | 75 Atk | 60 Def | 105 SpA | 60 SpD | 105 Spe
Notable Moves: Thunderbolt, Thunder, Discharge, Overheat, Flamethrower, Charge Beam, Switcheroo, Crunch, Fire Fang, Ice Fang, Thunder Fang, Signal Beam, Hidden Power, Howl
Manectric was a cool Electric-type already. Fire-type attack, Charge Beam to boost its Special Attack, Switcheroo, and a decent move to get around Rotom in UU thanks to Crunch. Seems like an awesome buff. If Choice Specs still exists in Gen 5, Switcheroo Specs is very viable when you consider the possibility of +2 SpA Thunderbolts.
Dream World
Notable Candidates taken in briefing:

Pikachu
Base Stats: 35 HP | 55 Atk | 30 Def | 50 SpA | 40 SpD | 90 Spe
Don't laugh. Yet. Light Ball just makes it insane on the Special Attack spectrum. Now it suddenly just got a little more deadly with the ability. Furthermore, it still retains Grass Knot, so don't think your silly Ground-types will work. Pikachu shall aim for the horn and not miss Rhydon! It is still a glass cannon, but one that can possibly pack a huge wallop. I wouldn't want to be a Pokemon that doesn't resist Electric and takes +3 Thundebolts. Well, maybe Blissey.

Raichu
Base Stats: 60 HP | 90 Atk | 55 Def | 90 SpA | 80 SpD | 100 Spe
Raichu is only noted because it is a sturdier version of Pikachu. Slightly faster too. Granted that Light Ball doesn't work on Raichu, but its moderate bulk helps. Just hope there isn't a faster Pokemon in the fray. Still, Raichu getting a buff is nice to have. Even if it is somewhat inferior to Pikachu. Being able to pull an Encore easier on slower Thunderbolt users is pretty cool.

Zapdos
Base Stats: 90 HP | 90 Atk | 85 Def | 125 SpA | 90 Def | 100 Spe
Technically, the Star of The Show<tm> for LightningRod is Zapods.
Pressure is a cool concept for Defensive Zapdos. Since it still has access to Roost, Zapdos just became MUCH more dangerous offensively. Hell, it even learns Agility and Charge Beam to add insult to the injury. Being a quick Pokemon as is, the only weaknesses it has is that it needs Hidden Power to bust through some of the Ground-types and possible lack of Shadow Ball, Extrasensory, Baton Pass, and Heat Wave. Still, consider that Zapdos was already deadly beast, LightningRod just made it scale higher of an offensive threat. Zapdos getting Lightningrod was a nice buff overall.
Finally, Lightningrod is very viable for Doubles and Triples battles. Sadly, not a very big expert on this one either, but Zapdos gets a huge mention for its resist of Earthquake.
Discuss.