Stealth Mechanics
Cocomajobo, I get the impression none of the DDO Developers are regularly playing Assassins in the stealth player sense.
Since the change of monster 'visual detection' range dropping from: 25 metres to 18 metre (metre is the correct spelling for a unit of length) is mostly irrelevant. Because it's quite easy to get well within 18 metre of a 'hostile' and not get detected by a generic mob. I presume you mean an 18 metre Spot Radius?
Even on a first life default path 'The Dark Blade' Rogue using random gear. Refer to any of my posts within the thread:
R.O.G.U.E Part Quatre: Call for Stealthy Players!, e.g. [
Post #428]. I'm using a default path first life Rogue and mostly using random equipment to partly illustrate that point.
That was a rather mediocre run and it could have gone more smoothly but that's mainly due to the flipping annoying dark-purple shadowfell (plane) visuals nonetheless it was done during Preview U45.
I play Assassins exclusively when on my home server. I don't tend to have much difficulty sneaking past most regular type mobs regardless of whether they are moving around. Although I do prefer to silently neutralise and thin out certain targets due to the current malfunctioning chain reaction aggravation.
Therefore I'm not a stealthy full mob avoidance player albeit even I can manage those "R.O.G.U.E Part Quatre" quests that require "mostly zero or minimal kills" without too many hiccups. I can inform you it's not generally a 25 or 18 metre distance that's a problem with potentially being detected. It's trivial to get much closer and not be noticed.
I assume you've mainly made the changes for people who are carelessly rushing through wilderness zones (with a Character without ranks in Hide and Move Silently). Or perhaps in quests where the stealthy player is already at imminent risk of getting rained down upon by arrows or spells, i.e. from already; active and highly aggravated mobs.
Spot distance was never the problem with Rogue Stealth play: Post Reaper mode, anyway. It's faulty chain reaction aggravation that's the problem, not spot proximity. Any Assassin worth their salt can easily approach a generic mob to Assassinate and not get detected and Spot range was never the main issue with the current faulty stealth mechanics (from the players perspective).
It's fair enough about the updated "Purple Visual Effect" Eyes for "Tremor Sense" mobs. For example; if you get random Champion or Caster combinations that maybe be able to detect stealthy players' via 'True Seeing' etc. Although to be honest you'll typically know long beforehand if a concealed but none directly visible Ooze or Spider is already close by when in Sneak via your Listen skill.
So you'd decided approximately a "body length" reduction in their 'audible detection range' is going to be a game changer when faced with an Ooze, I'm really not following how you are coming to these conclusions. The problem isn't the distance from the monster before it detects you, it's the fact once detected they are hard to shake off...
Let's take an example: the Oozes (Ochre Jelly) in 'Garl's Tomb' and 'The Troglodytes' Get' are some of the best "trackers" in the game! It's amazing how far they will faithfully travel to reach you. The early ones will go around corridors, climb up stairs continue following on, out of the room, along the passages... their range is crazy. All that time they are "locked on" to your position. They'll likely travel well over a few hundred metres in the hopes of digesting you.
It suggests you haven't been actually testing the stealth system using Sneak and playing through quests. To be honest it's looking more like you picked some figures at random to reduce both: Spot and Listen type checks. In the hopes it would look as though you were doing something greatly beneficial. Does reducing the Spot and Listen range reduce monster chain reaction aggravation from spreading; if the player is detected?
Reducing monster Spot and Listen distance was never asked for; just like removing the requirements for needing Sneak attack condition to Assassinate - certainly wasn't asked for by the Stealth enthusiasts. :-/
Perhaps you can enlighten us as to how you think those new reduced monster's "perception" distance values are highly beneficial to "balance" (or a major improvement) with regards to Stealth and Sneaking. I'm sure the stealth enthusiasts would forward to hearing your response, with a clear explanation of how you were conducting the tests. :-)