See - that bothers me somewhat. I was in the casino shop, and ... well, I was looking for a better 1-hander, so I picked up the most expensive one there. It was like 250k gold, and ... it was utter crap. An adamantine scimitar with 2d8+6 damage. That's it.
There's more expensive stuff in there, a full plate at 500k, a halberg at slightly less ... but really, nothing truly impressive seems to be there at all.
Anyways, I didn't claim it was wise to melee the ACW - it was just there, suddenly, around the corner and I was face to face with it. So I hit it, landed a big crit (for like a quarter of it's health) and figured 'oh hey - I can do this'. And I did. Also my troll dude doesn't do much of anything at range. He has tons of wands, but big enemies shrug those off effortlessly.
The cat lord was much worse, though. Holy crap, that was a fight for the ages. Haven't had to save scum for a long time, but I think I did that fight over and over again for .. an hour. In the end, I melee'd him too, just with substantial divine support =)