Cheiromancer
Adventurer
Well, the crippler is more combat oriented than the "skill monkey" rogue, so a pre-requisite that hints at greater martial focus seems appropriate. Proficiency with all weapons seemed a way of acknowledging that.
The prestige classes you list either have weaker abilities (the loremaster's, for example, are generally pretty minor) or are for much higher characters (e.g. the archmage). And sneak attack plus a crippler ability is two abilities at a level, not one. Consider too that getting a special ability every level is three times as fast as a standard rogue. A specialist might get 1/2 levels (50% faster than a rogue) but 1/level seems excessive.
It's your call, of course, but that's where I'm coming from in my comments.
The prestige classes you list either have weaker abilities (the loremaster's, for example, are generally pretty minor) or are for much higher characters (e.g. the archmage). And sneak attack plus a crippler ability is two abilities at a level, not one. Consider too that getting a special ability every level is three times as fast as a standard rogue. A specialist might get 1/2 levels (50% faster than a rogue) but 1/level seems excessive.
It's your call, of course, but that's where I'm coming from in my comments.