Honestly, we can't say really until 9th Hits.
The Bubble Theory is nonsense though. The only reference to that so far has been the Lizardmen picking up their cities and getting tae f*** out of there. What I can see however is them bringing the races closer together. High Elves and Dark Elves moved to the Tree Huggers home which just so happens to be closer to all the fighting. Then you have the floating cities of Lizardmen vanishing. Oh and the Ogres moving down from the hills. Seems a little coincidental.
I can believe the races will unite under various banners though. Bretonnia and the Empire, maybe Dwarves too? All the Elves in one basket. All the Chaos in theirs. Makes sense!
Round bases? I don't think so. Someone was already called out for photoshopping some pictures to show round bases. Plus they've been spending a great deal of money on new boxes with Square bases. Such a LARGE change seems utterly pointless. However, the shift to larger bases for Space Marines did open up a lot of questions.
Either way, it would be nice to hear something from GW for once