re Lumper vs Splitter: That's a good point -- fewer skills often implicitly include a wide number of specializations.
Mike and I both come from the same Old School. While the Book 1 list does feel too short, I think it still works -- especially for old farts like me who just want to play Traveller and have fun with it. Others need more detail.
MegaTraveller handled the problem by using cascades, which works, but I feel that MT went overboard on the list itself. I don't need to see "Halberd" in an official skills list.
I agree, the LBB1 list does feel a little bit short, but it works. You have to be willing to interpret things broadly and flexibly when there's no explicit skill for what you're trying to do- say, welding, or water-skiing. But a good group of players with a congenial GM will not have a problem with that.
Cascades are a nice idea. They help provide flexibility while keeping the basic career tables reasonably small and clean (which, to me, is a really important consideration). They're a good character customization tool, and they lend themselves easily and painlessly to houseruling if your campaign has particular needs not covered in the official rules. In the end, though, they're susceptible to the same sort of feature creep as the main skill tables. You're just kicking the can down the road. I think this approach, even at its worst, is still a lot less cluttered than jamming every possible specialized skill choice individually into a career table.
But again, it boils down to how many or how few skills you and your players want/need in order to be happy with the game. Think there's too many? Lump some together and eliminate others altogether. Think there's too few? Expand an existing cascade skill or create a new one. I can't speak for anybody else, but personally I don't want a great deal more complexity than CT offers out of the box. I do want a little bit more, and part of the beauty of the original CT design is that it's easy enough to add what I want, without breaking things or having to rewrite the whole chargen system.