I think that he is saying that 2e retained multiple dissimilar systems for what could, and should, have been handled with a single core system. And that the NWP rules, strictly enforced, prevented folks from attempting things that should have been general skills for adventurers.
For my part, I thought that 2e having any rules expanding on the NWP was a big step forward, and that putting points allocation for thiefly skills into the players' hands was a major improvement.
About the only thing that could tempt me with running a 2e game though is Birthright, it never quite translated properly to 3.X, but I loved that setting.
The Auld Grump
The the problem wasn't using experimental rules that still don't work or make any sense. Was fire-building a skill or feat in 3rd? Is it in 4th?
In 2nd they were entirely optional. Something for ideas, like the secondary skills, that gave people an idea and say "Hey there is more to your character than what was in the books here is some ideas."
To me they were more of a background tool. Like if a PC had came to adventuring as the some of a blacksmith, those common skills learned before going ot to adventure are at his disposal in a fashion.
Like a father working on his car (do they still do that with all the excessive tech requirements in today's cars?) and having his son help, there would be knowledge gained for a certain allotment of skill sets from that.
The farmers son would have learned a bit about the land, and plants, etc...
Likewise some classes would instinctively carry certain skill sets with them.
Before NWPs, if not just making up these skills based on background and common sense, where fire-building didn't exist; how did an adventurer light a torch without having fire-building as a skill?
Most of the people I know laughed at the NWPs and used secondary skills as a concept but not strictly. The ingenuity inspired by giving some things that weren't found in everyday for the time period was where NWPs came in handy. How many people started playing D&D knowing what a cooper did, or even thought about what went into making barrels?
Did you need an expert rogue to open a locked door? Half-barrel hinges the door can be lifted off of them with the right leverage, rendering the lock moot. Thus making a rogue not required in the presence of a blacksmith.
I also NEVER knew a DM that would argue a PC couldn't build a fire without fire-building. Again it didn't exist before NWPs appeared, and somehow adventuring parties of 1st edition AD&D, and early editions of D&D built fires, and lit their torches.
YOU think, is correct, because it doesn't need to be this "core system" that everything uses when the parts are unrelated.
I don't want a plumber coming to fix my outlets, and don't want an electrician working on my bathroom. The toaster is libel to flush, and I fear what my toilet would do when I go to use it.
The only thing the NWP rules strictly did was set an arbitrary limit, just like all editions have silly arbitrary limits. That is proven by the secondary system itself wherein a blacksmith could have more skills than the allowed NWPs.
Upon understanding that, then augment the system to the proper number of NWPs across the board for all, using it as a background tool. IF that doesn't suit your taste, then o like many others did and disregard the limits and cross-class penalties and such and the DM allow the use of ANY skill if the player can explain why his PC would know this. Again presenting itself as part of a background tool.
In a serious discussion an entirely optional system shouldn't hold the edition at fault for people using that system. You only had the limits of the proficiency system (weapon and non) if you used it. You could have taken and created your own system or flat out not used it and let player ingenuity determine what skills their characters had.