I finally beat the elite four members and the Pokemon league champion Iris a couple of days ago!!!
This was my team...
Keldeo level 61,                                  
Genesect level 62,
Emboar lever 60,                    
Krookodile lever 60,                                                                              
Druddigon level 59,                                                                                                          
Beartic level 59.                                                                                      

The final battle with Iris wasn't easy.(Of course) But it wasn't all that hard either.
Here is how it went...
My Keldeo beat Hydreigon with a single Secret sword attack,
Then Keldeo beat Lapras with two Sacred sword attacks,
Beartic beat Archaeops with Icicle Crash,
My Druddigon beat Iris' Druddigon with a couple of Dragon claw attacks,
Emboar beat Aggron with Hammer arm,
Krookodile weakened Haxorus with outrage... but Krookodile fainted thanks to a Dragon dance & Dragon claw combo.
So I blasted the remains of Haxorus' HP with my Genesect's Tecno blast.
And that is how I beat the champion of Unova!