Prince Martell is much closer to Littlefinger than anyone else in the series. In the books he has schemes all over the place. What he doesn't want is a war he will lose, but is perfectly fine with war. He just wants to make sure he wins it with as little damage to his own people as possible.
That's probably true. I just feel like the show set up this false ending to the Dorne story in Episode 9, with Doran apparently wanting peace with the Lannisters and no interest in revenge.
Based on how things have gotten reversed in the past on the show, I have a feeling episode 10 will involve some kind of turnaround, even if it's an indirect one that doesn't explicitly implicate the Martells.
As shoddy as the Dorne stuff has been, there'd better be more to it than "errybody happy, let's go home now"!
...it sounds like you haven't read the books, so at the risk of minor/implied spoilers, it's very likely we will see something like that this week, probably mainly in the form of Doran explaining himself to Ellaria. Doran has definitely not forgotten or forgiven the Lannisters using the Mountain to kill his brother and sister; he's just a lot more cold-blooded about it than most of the people around him.
I'm bracing myself for the big death at the end of book 5. Looks like it may very well happen, though would be stranger in the show based on some of the changes made.
Oh, that's definitely happening. They practically had a character wink to the audience about it a couple episodes back.