I've been wrestling with how to handle LOTFP Specialists in my Flailsnails OD&D game. OD&D Thieves have d4 hp, set skill %s, and are limited (varying with interpretation) to Daggers and Swords (AD&D pre-UA limits them to club, dagger, dart, swords (long, short & broad) and slings); leather armor & no shields.
Whereas LOTFP specialists have d6 hp, choose their own skills (which is usually a maxed out snaeak attack and stealth), can use any weapon, are limited to their leather when doing sneaky skills and can use shields.
Basically, as I've seen most LOTFP Specialists played, they are analogous to OD&D Assassins (d6 hp, any weapon, leather & shield).
Now I like OD&D/pre-UA AD&D class-based weapon restrictions. Fighters are the bad-asses using bows, pole arms, two-handed swords, morning stars, and the like. In 3E we reached this point where every PC was carrying reach weapons and crossbows and were all members of the Expendables or something, which is cool, but I think OD&D restricted weapons are cool as well and has it's own more-D&D-ish flavor.
Now I want to be a cool flailsnails DM and let people bring in their PCs and play them as they are used to.
Now I was thinking about 3E "munchkin cheese" and how the LOTFP could be seen as the Flailsnails munchkin cheese Thief when I realized something...
...in LOTFP Specialists are forever 1st level when attacking.
If you play a Thief in my Flailsnails game you are an OD&D Thief.
If you play a Specialist in my Flailsnails OD&D game you are a LOTFP Specialist that forever attacks as a 1st level character.