Diablo 3 Expansion Speculations

I know most of us are thoroughly enjoying Diablo3, but I know some are wondering about the next expansion already and who is going to to be the bosses for it. There have been hints in Diablo 3 about this and here are some considerations.
Mundunogo Diablo 3
There is a strong connection between 3 potential bosses and they are:

Adria – Adria the Witch! Diablo’s baby mama! Couldn’t be a more obvious baddie as an option for the next expansion, she used her daughters body as a ‘host’ to hold all 7 evils within which in short pretty much killed her and unleashed hell upon the high heavens… need I say more?

Malthael – The angel of wisdom, shortly after the worldstone was destroyed (by Tyreal) he left the angiris council going presumably mad and is wondering all pandemonium searching for the truths of life and death and could easily return to exact revenge upon Tyreal for the world stones destruction.

Imperius – A very upset angel, He most certainly still holds a grudge towards the naphalem hero and Tyreal for their sacrilege of the high heavens or so he sees it. He even threatens you with death and tried to kill Tyreal and the way the battle with Diablo went I doubt Imperius is very happy with the mess heaven was left in.

In my opinion, all of these honestly sound good to me to be boss contenders for the next Diablo 3 Expansion.
There most likely are already hints for the expansion(s) in the game. According to that leaked product slate, they had envisioned 2 as far back as early 2010. In September 2011, it was listed as part of their ‘core pipeline’ and would be out within 2-3 years.