RE: B/X Halflings kicking the ass of the AD&D halfling fighter-thief.
I call foul. None of this BECMI attack rank stuff or optional rules from fan publications. Pure B/X halfling versus pure AD&D halfling only.
Plus, we all know the thief would sneak right up and open with a big backstab anyway. :)
So here's the real skinny folks: no BECMI, no B/X Companion. My halfling gets nothing but the Basic and Expert set rules (typos and all) versus the AD&D fighter-thief, in all its glory.
8th level Halfling, AC 2, HPs 29, Strength 13 (all else average), D6 damage
Fighter-Thief, AC 8, Strength 12, Dexterity 14 (all else 13), D8 damage. Maximum fighter level is 4th, of course. No we're not going to be nice and give him a 17 strength.
The fighter-thief's average damage per round (DPR) is 1.125 against the B/X Halfling. With 29 hit points under his belt, it will take the fighter-thief 26 rounds to kill the Sheriff in a one-on-one fight.
The B/X Halfling's average damage per round (DPR) against the fighter-thief is 3.6. This is calculated from an 80% chance to hit (per the Expert rules, an 8th level Halfling needs a 6 or better to hit AC 8, +1 for the 13 strength) multiplied by his average damage of 4.5 (D6 for all B/X weapons, +1 for the 13 strength). In order for the fighter-thief to survive 27 rounds...the only way to ENSURE he will win the fight, since the Sheriff gets an individual initiative bonus (not available to the AD&D character) and is thus more likely to kill the multi-class character in round 26...in order to last 27 rounds, the fighter-thief will need at least 94 hit points.
That means he'll need to be level 4th / 43rd. That's 43rd level thief...which requires an experience point total of 14,520,002. Fucking ridiculous. Yes...your fighter-thief WILL be more powerful IF YOU HAVE 121 TIMES AS MANY EXPERIENCE POINTS.
But, hey...what about that whole backstab thing?
Well, leaving aside the whole "fair fight" question (and who's to say my halfling with his 90% chance to vanish into the underbrush wouldn't get the drop on the cowardly fighter-thief?)...LEAVING aside that question, WHAT IF we spot the pansy fighter-thief a free attack?
Well, assuming he's at least a 13th level thief, that's quintuple damage in AD&D. He also receives a +4 bonus to hit AND the halfling loses his shield bonus. His average damage from such an attack will thus be 11.25 (50% chance to hit X 4.5 average damage X five), reducing the stalwart Sheriff's hit points from 29 to 17.75.
The AD&D character will then be in a fight for his life. It will STILL take him another 16 rounds to finish my B/X character. He'll need to have at least 58 hit points himself to sustain the onslaught of my 8th level character. That means, on average, he'll need to be AT LEAST level 4th / 25th.
That's a total of 6,600,002 experience points. Only 55 TIMES the number needed for the B/X thief to reach 8th level (120,000). Wouldn't that mean the B/X Halfling is 55 times as powerful as the fighter-thief?
What does that say to you? To ME, it confirms that the very IDEA the AD&D halfling fighter-thief is more powerful than the B/X Halfling is patently ridiculous. Even giving him a surprise attack with QUINTUPLE damage, the AD&D character is probably a dead f'ing duck, except in the highest level AD&D campaigns.
An Epic Level character...to take out an 8th level Halfling?
I don't know if folks are insane or just ignorant. Leave the thieving to the thieves, and be proud to play the Halfling character. Jeez...I don't know what else I can say here.