Gunna be honest when i saw HP water i instantly thought "GIMMICK!" However after thinkin about it. Water hits Rock, Ground, and Fire for SE. Basically it hits grounds harder than ice beam (in rain). It his Rock types for SE. And it his Fire Types for SE.
Genesect @ Expert Belt
Trait: Download
EVs: 72 Atk / 252 SAtk / 184 Spd
Naive Nature
- U-turn
- Ice Beam
- Hidden Power [Water]
- Thunder / Bug Buzz
This is a pretty cool Genesect set that I've been toying with on rain teams. Although it's essentially just the standard EBelt set with HP [Water] slapped on, it can do things the original could only dream of - namely break apart most its standard checks, e.g. Heatran, Terrakion, Volcarona, Chandelure, etc - with only one "stone". What makes it work is the surprise value - when was the last time you expected Genesect to have a Water attack? In BW2, any surprise KO on the opponent can shift the momentum in your favour greatly.
In case you're wondering, Expert Belt HP [Water] is better than Douse Drive Techno Burst. Whilst it has 1 less BP when it hits SE (70*1.2=84), it also grants benefits to the other moves, whereas Douse Drive solely benefits Techno Burst.
U-turn and Ice Beam are obligatory. The final moveslot depends on what you're more interested in hitting harder - bulky Waters (especially Jellicent/Gyarados) or bulky things that resist Water/Electric such as Ferrothorn/Kyurem-B etc. Bug Buzz also allows you to 2HKO most Jirachi when you have an +1 boost in SAtk.
Although I haven't slashed it on this particular set, I think an EB set with U-turn/Thunder(bolt)/Ice Beam/Flash Cannon also might be viable in this metagame - especially considering Kyurem-B is quite popular at the moment due to being newly sent into the OU metagame. It also hits Terrakion very hard.
Its the list of counters to genesect that hate HP water. The amount of times heatran and terrakion have switched in on my genesect (i use giga so terrak is fine but still) is a huge number! And HP water will in affect have STAB in rain!
Also with Thunder on the set you can spam 100% accurate Thunders. However I would concider changing that. Personally id accept Ice Beam handels flying types. So id go giga > thunder to give you more life span whilst posing a threat still to waters aswell as killing Gastro and Quag.
But yeah i love your set.