I can see why they toned down Euron's most diabolical elements ever so slightly, but then a more surrealist approach to the show would've perhaps been more interesting and bold to a certain extent.
Cutting certain aspects of AFFC and ADWD was logical, but if they were going to introduce Dorne and the Iron Islands they should've done them properly. I wouldn't have even been against both plots being introduced earlier in Season 4, since they stretched ASOS over two seasons. Euron's meant to murder Balon in that timeframe anyway. And since we aren't restricted to a select few POV's in the show we could've perhaps had Doran introduced before Oberyn went to KL etc.
For me the fundamental problem is that the writers just didn't plan properly beyond the Red Wedding at all. They admitted that it was the big moment they always wanted to reach. They got away with it in Season 4 because the source material they used remained strong, but you could always see there were some problems emerging in regards to pacing and writing. It became a lot more obvious after that.
Although I thought last night was alright and far better than the last few episodes of Season 7, so if nothing else it'll still be solid entertainment.