Question

Want to know. Thank you in advance.

Answer 1

What Ghetsis wants to do is to freeze Unova using Kyurem, and steal every Pokemon, rather than releasing them.

Source: I've played W2 and this is what he wants...

Answer 2

Same as BW1.

Rule all Pokemon.

Answer 3

http://bulbapedia.bulbagarden.net/wiki/Ghetsis

In Pokémon Black and White 2, Ghetsis turns out to be once again:

Ghetsis is behind TeamPlasma's activities. This version of Unova's villainous team
is not attempting to release Pokémon, but instead take over Unova. He
wants to freeze Unova so that Team Plasma can steal every Pokémon in
the region. He has appointed Colress as the new official boss of Team
Plasma and recruited Zinzolin to help him. After being defeated at the
Giant Chasm he suffers a mental breakdown and is escorted away bya
memberofthe Shadow Triad. Later, in Icirrus City, the Shadow Triad
reveal that Ghetsis has lost heart and is no longer capable of any
further criminal deeds.

He is insane in BW2.

Answer 4

To take over the world like any other team.