Indeed, to me the implications are quite clear: we should use LotFP's Specialist as a "conversion kit" for any custom class (or so-called "Advanced" class such as those in the Advanced Edition Companion) that we want to bring into our Basic D&D-ish games. As Raggi himself puts it on p. 71 of Referee,
"Assassins and Bards are Specialists. If the adventure or supplement text mentions specific power that these classes might have in other games, just grant it to the particular NPCs."
What Raggi suggests we grant to particular NPCs could be used, as Beedo has ably demonstrated, to streamline the process of bringing oddball PC classes like Rangers, Bards, and Jongleurs into the mix of our campaigns. Need a sea pirate with sailing skill? Make Sailing a Specialist skill and make Sailors Specialists.
Using this logic, I could port the Delving Deeper Bard over to the LotFP Specialist paradigm -- or, I suppose, simply steal Beedo's Bard. I would also like to graft Ranger skills* like Tracking onto the Specialist chassis:
Tracking - "Familiar with the signs left by humans, humanoids, and various other creatures as they make their way through the wilderness, rangers can discover and follow the trail of those they are pursuing -- sometimes even in the worst of conditions."
So the standard Ranger (according to Brave Halfling) would have points in Tracking, Move Silently, Hide in Shadows, Bushcraft, and Hear Noise. Any Ranger wanting to take the "Damage Bonus" option instead of the "Additional Skills" option (see Delving Deeper: Ranger) -- I've been using the former to represent northern Achelonian monster fighters -- could simply spend one of their initial allotted skill points to gain that ability, maybe swapping out Hide in Shadows and/or Hear Noise and instead spending a point to get that damage bonus vs. evil humanoids and giants.
Under this system, the standard LL thief would simply be a Specialist who spends points on Pick Locks, Find and Remove Traps, Pick Pockets, Move Silently, Climb Walls, Hide in Shadows, and Hear Noise.
After chucking in the Bard and Ranger skills, and changing some of LotFP's thief skill names back to their Labyrinth Lord equivalents,** my custom Specialist Skill List would look like:
Find and Remove Traps [EDIT: Tinkering in LotFP]
Hide in Shadows [Stealth in LotFP]
Lore [described here]
Move Silently [Stealth in LotFP]
Performance [described here]
Pick Locks [Tinkering in LotFP]
Pick Pockets [Sleight of Hand in LotFP]
Tracking [see Delving Deeper: Ranger or description above]
It is too late for me to make the LotFP Specialist conversion in my current Labyrinth Lord campaign, because it would seriously change the nature (and , I think, potency) of our home-brewed 2d6 Bard class, currently active in play. But one day, after the current party retires or dies (TPK!), maybe I will run my NEXT Lands of Ara campaign using a more lean and mean ruleset, mostly using Labyrinth Lord but with the LotFP Specialist thrown in to replace all non-core custom classes including the standard LL thief. I would also be ditching all the AEC crap as well, except, perhaps, the expanded spell lists. But that is for . . . the future?
* I am stealing these Ranger abilities straight out of Delving Deeper: Ranger. Raggi's Bushcraft skill already covers foraging/wilderness survival (p. 33) as well as direction sense (p. 34).
** Thanks to Mr. Raggi for providing skill name conversion guidelines on p. 70 of Referee.