I don't claim to be a pro by any means, by my favorite Pokemon are Blaziken, Gardevoir, and Luxray. 2/3 of them are almost never used competitively.
For Gardevoir, I think letting her learn Ice Beam would make a world of difference. It'd help her take out Dragons, those Bug Types, and it'd help make her more all-around if you combine it with Psychic, Thunderbolt, and Energy Ball/Shadow Ball (I believe it is that she can learn).
For Luxray, a STAB Elec move would really help that's higher than 90 Base Power. He can't learn Volt Tackle, and Wild Charge is the best he has. I have mine know Superpower, Crunch, Volt Switch, and Wild Charge. Since he's mainly using Superpower, Volt Switch isn't affected by the power drop and can get him out of there, or can simply use that when I send him out first and can get a better matchup going.
Official President of the NST 'But Neku, I thought you couldn't afford to lose? Give up on yourself, and you give up on the world.' - Joshua