As many others have mentioned here, I believe the next episode will be sort of cliched with some tiny twists (like Rickon dying or not blah blah) but I feel that the last episode will be the interesting one especially considering that it is going to be the longest in GoT history
! 1. R + L = J reveal
2. Dragons coming into Westeros perhaps
3. Wildfire explosion in Westeros maybe
4. Death of a few high profile Lannisters
5. A red wedding revenge maybe
6. Euron Greyjoy. I mean seriously, we have hardly seen this guy this season and he could very well end up as an intimidating opponent later on
7. And finally of course, the white walkers