- Dany meeting Barristan and seeking passage to Slaver's Bay
- Arriving in Astapor and meeting Kraznys and Missandei
- Arranging to "purchase" the Unsullied
- Sacking Astapor
- Leaving Astapor with her followers
- Meeting the Yunkish sellsword captains
- Taking Yunkai and being hailed as "Mhysa".
Now, I can't speak for what goes on in D+D's minds, but logically merging Meereen and Yunkai makes the most sense for the show. While I don't like treating TV audiences like idiots (their not), the show does need to streamline information, and having three very similar cities in one location is something that I don't think works on TV. Also if we have both Meereen and Yunkai, Dany's season 4 arc will be a repeat of the 2nd half of her S3 arc, just stretched over more time. That's going to come across as trite repetitive filler. In the books each city is taken over the course of a chapter, but you're suggesting stretching single chapters over entire seasons. Not going to work. It would make much more sense to just have Meereen and Astapor, and after Dracarys to take elements from Dany's conquests of Meereen and Yunkai, and merge them into a few exciting episodes. Then S4 can cover some of her DWD material.
Dany's whole story line in Slaver Bay was a trite repetitive filler
In season 3 the focus will be on Robb/Cat's story (and also Arya), with the other stories being streched out more. That will have to include Dany's.
I don't think any city will be merged, there's no need for that, they'll have 3 seasons yet to get where we are in the books, and I don't think they rush it, what are they going to do when there are no more books left??
And yeah, Robb/Cat will be the main story this season, but Dany and Tyrion are by far the most popular characters in the show, they will give them as much screen time as they could, just look at season 2 they created a whole new (and poorly written) story to Dany since they desperately wanted to give her screen time