Having found the answer to this eleven days too late to post on the bioware forums, I'm mentioning it here in case it helps someone else.
I was having a regular crash in the DLC at Honnleath: "Exception Raised ... [memory address details] ... Do you wish to debug it?" with yes and no buttons. Yes quits the game cleanly, No leaves the game running but unresponsive and requires a force quit. I actually gave up playing for over a year becasue I couldn't get past it.
The solution -- for me -- was to uninstall a mod (that I had long since forgotten about) in the ~/Documents/BioWare/Dragon Age/packages/core/override folder. Unistall in this case just meant drag it out of the folder and restart the game.
After that I was able to recruit Shale and carry on. (At last!)
Some memory-hungry texture mods have been listed as a possible cause of other crashing bugs, while equipping items or entering new locations for instance, but I hadn't seen that answer linked to this problem, although "Exception raised" crops up repeatedly in the old forums. Fingers crossed someone else finds their way to this and it solves their problem too.
mileyvery-happy:
