Prediction of the cover:
Neo sannin with the four previous hokages in the background.
Prediction of color page for chapter 632:
A color page for chapter 632 dedicated only to Sasuke, Sakura, and Naruto, either riding on their summons, or with their "that" attack.
Prediction for Sakura's power-up:
Slug Sage Mode. Why?
1.) Sakura stated that she "can compete with the two."
I cannot think of anything else that will be able to compete with Naruto and Sasuke, other than Sakura's own sage mode. The use of an axe, or genjutsu alone is not enough for her to state that she can be on the same level as Naruto and Sasuke. Also, since it will be difficult to compete with the two with battle skills only, I think her slug sage mode will have a different characteristic to that of snake sage mode and toad sage mode. My prediction is that slug sage mode will have strong regenerating abilities. She might not reach the power to fight compared with Sasuke and Naruto, but she may be the most difficult to kill/die in battle while in slug sage mode. (After all didn't Madara say, that Hashirama can heal without using hands? I believe his sage mode allowed him to heal instantly. If he has the Slug Sage Mode, the effect will go for Sakura as well)
2.) Tsunade said that she is the only one who can use Byakugou.
I think this is true. Therefore it means that Sakura's power up has to be an easier version of Byakugou or, something completely different.
3.) Last generation surpasses the previous
Since, this is most likely her last battle, I believe that Kishi will follow up with what other characters have said about Sakura.
Kakashi, "Not only that. She's a genjutsu type. She'll probably be a stronger kunoichi than the Fifth."
Chiyo, "You'll probably be a greater kunoichi than your master."
Sakura gaining the "Slug Sage mode" which Tsunade couldn't master, shows that she has indeed surpassed her master.
4.) Myobokuzan, Ryuchidou, and Shikkotsurin
Kishi made Kabuto state all three of these places for a reason. It is very unlikely that they are not going to be addressed. One place is for training toad sage mode, another place is for snake sage mode, how far-fetched will it be that Shikkotsurin is for slug sage mode?