Oh word I totally forgot about that scene. Sort of highlights the reason the whole Dornish thing is a mess. The fact that other houses simply exist doesn't really give us anything to go on re their interests, motivations, stances on Doran as a leader, ambitions, etc. But I'm really not interested in the show digging into Dornish rivalry politics given how much it's elided of the more interesting, say, Northern rivalry politics. They're definitely hitting a weird "uncanny valley" here where the non-lead-character Houses are too poorly drawn to be interesting, but still present enough that their absence gets conspicuous. Like what in the fuck have the rest of Robb's army been doing since the Red Wedding? The Bolton plan to consolidate power by marrying Sansa was always thin because we never saw tension between Bolton and Karstark or Umber or whatever.
The show politics in general have been very bilateral in nature. Even when Stannis was at war with everyone, he was only really engaged with one enemy at a time. Littlefinger, instead of playing a web of allegiances with Lords Declarant that have internal rivalries, only really dealt with The Vale as a body.
I think they have shown that Doran is a recluse and has isolated himself from the rest of Dorne so while it is strange there are no other lords present it is kind of explainable. What happens next in Dorne is going to require some sort of action outside The Water Gardens (or what was the point?)
Will we even see that though or will Ellaria abandon Dorne and take up a Quentyn trip to Meereen to bring Dany to Westeros. Her meeting with Tyrion would be interesting. Tyene could go to Old Town and the other two could continue their terrorising of KL which would put the story back onto the book path (obviously without Arianne and FAegon) In the books I think Doran is going to die in the most shocking way possible.... old age.
They showed what happened to Robb's army, his banner men were killed at the twins and the men scattered.