Honestly, I forsee some big twist coming at the end of Destiny one that will continue in to 2. After we defeat the new new vex and cabal enemies The speaker, fearing we are becoming too strong, will either Banish us or send us on a mission outside the system. The speaker will then send someone or something after us to be rid of us without worry. Then, somehow, we will be revived, the speaker will get wind and try to stop us from making it to the city. Knowing how thing go after this, right as we are about to kill him, the ones that he actually is working for will come to save his bacon from the fire. The reason I say this is look at what he did to Osiris as he began to gain more power (and even nearly became the next speaker). He knew things the current speaker doesn't and I would be willing to bet he found out something about the speaker before being banished and was probably the reason he was banished in the first place.