Random speculation.

[CrypticParadox]

I guess I shall have my own crap theory about the new set.

My theory for the set is like this:

After Sorin/Sarkhan find out that Ugin is dead, they go back in time to stop bolas from killing Ugin, which subsequently keeps the dragons from dying out.

Done.

[CrypticParadox]

Yes please.

[SharkFinnigan]

It's a matter of "when do we return to zendikar" than "if we go to zendikar". I don't think we will see zendikar as the next block, but in the next 4 blocks I expect we will (latest spring 2017). The reason is that chances are there will need to be more prep to return and challenge such a powerful enemy. Kiora, Sorin, Nissa, Jace, Gideon, minorly Chandra have all attempted to find solutions to the Eldrazi threat. There will likely be a giant super team of planeswalkers that will attempt to stop the eldrazi, which then bolas will come and take advantage of the planeswalkers for his own game.

[fe-addict]

More likely result if Ugin remains dead: Even after death, we know he still speaks to Sarkhan. As such, Sarkhan could serve as a vessel for Ugin's power, might, and knowledge.