With the buff of Techno Blast, Genesect has a 100% accurate and slightly stronger Hydro Pump, Thunder, Fire Blast, and Blizzard. Another blessing is that Genesect's form changes are very subtle, something most players facing Genesect may overlook completely (A small section of his cannon changes color to the drives).
Rain support/Weather Killer
Genesect @ Douse Drive/Chill Drive
4HP/252 Sp.A /252 Spe
Thunder
Techno Blast
Flamethrower
U-Turn
A Nice example of what the new Techno Blast can do. With Rain up and running, Genesect can begin spamming Thunder like it's no tomorrow. U-turn is the same old same old, hit a Darkrai or another threat and get out fast to let Kyogre set up. Techno Blast now depends on your tastes; You can now have either a Douse Drive for a Rain boosted Hydro Pump to surprise Sand teams and the occasional Groudon, or if you want to eliminate Groudon and other Dragons quickly, use a Chill Drive for a quick Blizzard boosted via Download. Flamethrower is to shoo away any Steel Types away that Aren't Heatran, as well as giving Hail something to think about.
And while this was kept in mind for mainly rain teams, it is far to easily adaptable for other purposes without getting your EVs in a knot. With these new toys, this Genecidal insect will be all over the Uber tier within a few weeks.