Ok, I do some tests and...
My frist gameplay = Human Female Rogue, Normal mode, 20h+ ( Banter was low, around 30 min+ each banter)
My Second gameplay = Qunari Female, Rogue, Hard mode, 20h+ (Amazing banter, every 5 10 min max, I even had banter that Viviene commented with Sera about our relationship, Amazing *>*
My third Gameplay = Elf Female, Rogue, Hard mode, 20h+ ( Very low banter, only Solas and Sera banter sometimes between them , the rest remained in complete silence)
All gameplays I made the same choices . I was not in the mountains at the beginning , I chose the Templars side etc ..
I will create again one Qunari to see if it really has something to do with it.
On my 5th playthrough now and no workarounds are working. I have gone 2 hrs without banter. After 4 complete playthroughs, i know many of the conversation chains and even where i get the most banter. I am doing the same workarounds that I learned about since 2nd playthrough.
My 5th playthrough - Female Dwarf Archer. It is odd that I am playing an Archer again and getting very little banter (about 1 every 2hrs or not at all). My first playthrough was an Archer as well - Female Elf. And in both cases, I romanced Sera. My first playthrough I had less than 25 random banters with over 144hrs. Note = I did spend a lot of time in Western Approach and Exalted Plains two regions that appear to be broken banterwise.
1st PT on PC Normal with friendly fire. 5th PT on PS4 Hard with friendly fire. The 3rd and 4th PT were Hard and Nightmare without friendly fire. I wonder if FF is a part of this. I also had lower banter on 2PT with Hard friendly fire.
Strange you had great banter on Qunari. I had the same. Female Qunari Warrior (3rd playthrough). I had so much banter it was crazy. People became couples and I was able to ask about it in Skyhold. I actually reached a point where Cassandra and Varric were joking with each other - both had apologized for past wrongs.
I edited this to add something I saw in another post. On both my 1st and 5th playthrough, I sided with Mages as allies and went through mountain. 2nd PT sided with Templars and charged. 3rd PT sided with Mages but conscripted and went through mountain. 4th PT sided with Templars but dissolved and charged. I have had the most banter in 3rd and 4th PT (with workarounds). It was firing as Bioware described. And no skipping of dialogue in a conversation chain.
Note: I never realized during 1st PT but when I did get banter, their dialogue was the 2nd or 3rd comment in the chain. I only realized after hearing a complete conversation chain from start to finish in a different PT. So it looks like you will miss dialogue if the banter does not play as expected.
So I figured after great success in 3rd and 4th playthroughs, I had finally figured out the workarounds for my banter bug. But it has been horrible this playthrough. I even switch up parties and areas and still nothing. I had a weird audio glitch early in the game (some loud horrible sound). After that I noticed a weird thing - One person said their banter 3 times in a row. What I mean is usually each member will rotate. This person talked every 10 mins and said the dialogue I had heard before in a chain but no one else talked in the middle. Also, I am having horrible combat issues this time - Two of my party members will not attack unless I click "Attack My Target."
2 PTs on PC. 3 on PS4. It is not the hardware. There is a or several defects in the code affecting random party banter. We should not have to do workarounds just to get it to work as expected. And many of us still have a point where none occurs even with the workarounds. I know I have not exhausted banter - I have heard many conversations across several playthroughs so i know what should be happening. This 5th playthrough, my game is really broken.
I have enjoyed the game so no worries. I am going to stop this playthrough. The whole point was to video capture banter I had not heard in other playthroughs - was trying out new combinations. So no reason to continue playing with it not firing.