There is alot more foot traffic down there now, folks going to and from a certain mushroom, and searching for exploration areas. I suggest that the areas between the Abyssal and the Umberhulk Quest zone (further into the Underdark?) have the same spawn rate of mobs as the Abyssal and that first zone, thereby giving the UD the truly deadly feeling it deserves. The crossroads, currently with the acidic chicken and giant helldogs, are a more dangerous place then most of the UD zones currently. Just a suggestion, as the forum thread name suggests..
I've seen Drow, Illithids, and other very powerful things in the first area as it is. As it is nearer to the surface I would expect them to remain more rare, as they currently area. As you go deeper into the UD it becomes more dangerous.
I've been chased around by Drider and Illithids every time I've gone down there on each of my characters. I think its sorted as it is.
Having recently played a character who went down there on a regular basis, and having had to turn back on several occasions due to just how dangerous it was despite having FE Elf/Undead (and yes, I used a bow, but even if I pulled out a sword with magic weapon and fully buffed, it was too tough, and not all fights could be avoided), I can say with complete honesty that the UD is much, much more dangerous than the crossroads.
Honestly, the crossbreeds are above average, they aren't really terrifying unless they catch you by complete surprise.
While I've come across some really scary groups and watched some awesome NPC battles in these areas, I wouldn't mind some upping of the danger, with perhaps some more secret hiding places or passages.
It wouldn't be so bad if climbing didn't take you out of stealth.
(Ooh. New suggestion thought...)
I think going down there is about as dangerous as travelling near sanctuary was in the old days. Actually probably more so and sanctuary was much deeper than the upperdark.
Seen mind flayers, 1-3 umberhulk behemoths, spawns of 5-6 driders. Not to mention the magic eaters that pop up when you try to buff. I quite like the underdark areas as they stand. I'm all for making even deeper more dangerous areas though.
Edit: Lets not forget that only certain types of characters can travel freely down there due to all the climb checks. Though anyone can get around. It can be extremely tedious.
I trust the OP, for I know the player has been playing in this particular area for at least two months.
My point was, that after the first zone, where it is quite dangerous, the next three are barren of any spawns whatsoever, so much so that any PC's that go down on a regular basis, know that they are safe once thru that zone. Not until they reach the Abyss do any spawns occur at all. Perhaps this is as intended, but it seems like the predators of the two zones at either end, would not simply sit there, but rather wander in search of food (us). ..
and yes! a wonderful one is to have climbing not break stealth, unless you fail the climb check? Tumbling down a cliff side would certainly be noisy!
I've been down there before and wasn't so barren in those areas O_O ive ran into drow patrols before.. it was brutal