I dont refuse them. But I have not seen a singe logic word on the balance issue yet, and its true.
So am I illogical? You haven't referred to my post once. What is your argument? That an LA +2 Drow (no racial levels) vs an LA +4 (4 racial levels) is unbalanced towards the drow? Compare the following (Keep in mind I suggested that in a combat-heavy campaign the LA for doppleganger be reduced to +3 and the required number of Monstrous Humanoid levels be reduced to 3).
Pay attention please Simulacrum. No one is joking, and there is no pulling wool over your eyes, just cold hard facts. Each has been placed on the exact same path, a dextrous rogue with some combat ability. As you suggested, the drow version is going for assasin, none of the others have enough rogue levels.
Drow Rog5/Ass2 (Humanoid [Elf])
6+5d6+7 hp (30.5 hp)
Stats: Str 10 Dex 18 Con 12 Int 14 Wis 8 Cha 15
[Ability Increase: Dex]
BAB: +4
Saves: +2/+11/+0
AC: 19 (Mithril Chain Shirt +1)
Abilities: Darkness 1/day, Dancing Lights 1/day, Faerie Fire 1/day, SR 18, Sneak Attack +4d6, Trapfinding, Evasion, Trap Sense +1, Uncanny Dodge, Death Attack (DC 14), Poison Use, Spell Use (1st level spells: 2/day; 2 known; 2nd level Caster).
Feats (3): Dodge, Weapon Finesse, Mobility
vs
Doppleganger Rog1 (Monstrous Humanoid [Shapechanger])
8+3d8+1d6+15 (42 hp)
Stats: Str 12 Dex 18 Con 16 Int 14 Wis 12 Cha 15
[Ability Increase: Dex]
BAB: +4
Saves: +4/+10/+5
AC: 23 (Mithril Chain Shirt +1)
Abilities: Continuous Detect Thoughts (DC 14), Change Shape at Will (Cannot be Dispelled, magical in nature; pierced by True Seeing), Sneak Attack +1d6, Trapfinding
Feats (2): Dodge, Weapon Finesse
vs
Combat Doppleganger Rog3 (Monstrous Humanoid [Shapechanger])
[only 3 Monstrous Humanoid Levels, only LA +3]
8+2d8+3d6+18 (45.5 hp)
Stats: Str 12 Dex 18 Con 16 Int 14 Wis 12 Cha 15
[Ability Increase: Dex]
BAB: +5
Saves: +5/+10/+6
AC: 23 (Mithril Chain Shirt +1)
Abilities: Nat Armor +4, Continuous Detect Thoughts (DC 15), Change Shape at Will (Cannot be Dispelled, magical in nature; pierced by True Seeing), Sneak Attack +2d6, Trapfinding, Evasion, Trap Sense +1
Feats (3): Dodge, Weapon Finesse, Mobility
vs
Half-Fiend/Half-Human Rog5 (Outsider)
6+4d6+15 (35 hp)
Stats: Str 14 Dex 20 Con 16 Int 16 Wis 8 Cha 15
[Ability Increase: Dex]
BAB: +3
Saves: +4/+9/+0
AC: 21 (Mithril Chain Shirt +1)
Abilities: Smite Good 1/day (+5 damage), Darkness 3/day, Desecrate, Resistance 10 (Acid, Cold, Electricity, and Fire), DR 5/magic, Nat Armor +1, SR 15, Sneak Attack +3d6, Trapfinding, Evasion, Trap Sense +1, Uncanny Dodge
Feats (3): Improved Initiative, Dodge, Weapon Finesse
These aren't fully statted characters, but enough for us to get an idea about them. Your big contenders, the drow rog/ass and the half-fiend (celestial, whatever, these are evil bastard rogues) rogue are clearly actually
worse in combat. They both have lower ACs (much less in the drow's case), less BAB (in the half-fiend's case), and much poorer saves (specifically Will Saves - Although the drow would at least get a +2 vs spell-like and spells and an additional +2 vs enchantments, still not as good as the doppleganger (who is also immune to charms)). I mean, those are things that measure "combat ability" right? Oh, and hit points, the most glaring oversight in your argument. The doppleganger is 1.3 times as sturdy as either the half-fiend or the drow.
The drow does, admittedly, have some nice abilities like a high sneak attack and uncanny dodge (as well as evasion). The doppleganger doesnt have those abilities (yet) but his innate Change Shape which you so trounce is light years better than Disguise Self, what the assasin probably chose to learn to be this kind of rogue. Not only can the assasin's version be dispelled and disbelieved (its an illusion) it only lasts 20 minutes! The half-fiend is going to have to spend some money if he wants that kind of effect, and the only thing he really has going for him is his many resistances and the ability to cast darkness (presumably before fleeing).
The fact that I measured the doppleganger at the lowest level you can play one and showed that it is stronger than both of your suggestions should tell you something: do a little research before you start spouting off to everyone. If you really find the doppleganger so weak, my suggestion of a combat doppleganger (for campaigns where you cannot fully take advantage of the intrigue and deception a doppleganger can cause) will show you its easily the best character listed. Its basically like the regular doppleganger, but more hp, more rogue abilities, and better feats and BAB than even the drow.
A few words about Detect Thoughts (I looked it up). As far as the Detect Thoughts DC, it is Charisma based, the formula being 10+1/2 HD+CHA. The spell description appears to indicate that each round you concentrate enemies have to make a new save, since you can redirect it to a new area (60 ft. Cone). Also, it is unaffected by SR. All in all, a very powerful ability in and out of combat for it to be continuous (ie- not wasting a turn casting it each round) since eventually everyone rolls a 1 and then the doppleganger is in (presumably until he resets the cone's direction).
Thanks for reading all the way through,
Technik
Edited: Change Shape
is magical in nature, as it is a Su.
Edited2: Realized Half-fiend only had 8 levels total, raised him to Rog 5 (and adjusted stats accordingly).
Edited3: Miscalculated Doppleganger's feats, edited for correctness. (Thanks Sollir!)