Invastions ala Dark Souls

Wouldnt it be awesome? If you could invade other instances if both sides agreed on it? (switched a button in character screen or something that would allow invading your instances).

You could get some rewards for it, like incresed drop rate if you allow to invade you.

I don't think that this game really fit the needs required for dark souls style PvP to be valid.

Cut throat league will be similar

Yep this will already be coming, its called Cut-Throat league. You can invade anyones instance and you are automatically hostile.

Could I move my default character to Cut Throat League ?

no