I have 156 hours (holy smokes didn't even notice) and just finished the game. I restarted a number of times to find a character that had the right specs for the dialog options I wanted. The character I used to finish the game was a Paladin with very high perception, intelligence, and resolve... min maxed pretty much. A tank and pretty much nothing else.
I played the game on hard. After working through most of the companion arcs I ended up with Eder, Aloth, Durance, and the Grieving Mother. The other two characters were my paladin and a min/maxed cipher. I found the adra dragon and Returned Raedric much more difficult than the fight with Thaos. In fact the fight with Thaos was over before it started.
Both my ciphers had unique fully enchanted blunderbuss weapons. At the start of the battle both ciphers cast amplified wave and knocked down the 2 minions. The ciphers then turned and fired their blunderbusses at Thaos.... he exploded. I checked the damage log on both attacks, it was upward of 200+ damage from both characters. I then just mopped up the rest of the trash.
The ending does seem rushed. Although, the way the story is setup I'm not sure how it would feel much different. When all those questions are built up so high when the answers flow in it will feel short almost no matter what they do. But still it did feel rushed some what.
I still have a lot of questions after the ending. I'm curious if the gods are individual machines hidden around the world? Or are they just one machine acting out each part? How do they execute their power with no avatar? Soul manipulation? Did Thaos gain the ability to move his soul at will from the machine? And there are many others.
The ending slide for my character makes it sound like there is more yet to come.