I really have a hard time understanding these crafting changes. Looking at this rationally. If you divide people into 3 groups (probably can be more, but generalizing here)
1) People that love crafting/harvesting, would rather craft than do other things if given a choice.
2) People that are part-time crafters/harvesting, dabblers of crafting, or just craft/harvest for money during downtime.
3) People that hate crafting/harvesting, will only do this if they stumble on to nodes while adventuring or if required to do so because of money or unavailable items that effect there other gameplay. Overall these people would rather be doing something else.
So which of these groups of people are you appealing to?
Group 1 loves crafting and wants to do all the crafting content possible, yet only gets to experience 25% of the crafting/harvesting content.
Group 3 Probably will be neutral to this change.
Group 3 wont care because crafting/harvesting doesn't even matter to them.
Lets flip this for group 3, lets say you did the same thing for dungeons. Based on your chosen class you can only go into 25% of the dungeons. We made this really cool content, but you can only dream about it, we know you want to do it, but we are going to taunt you with it by forcing you to choose which part of the fun content you want to do. You can do as much of the unfun content as you want, but are not allowed to do all the stuff you enjoy, you have to choose.
So unless you are trying to get crafters to purchase multiple accounts and make multiple characters to experience the content, its really hard to see how this even makes sense.
The only way I could possibly see this system working, is if each line was so content heavy and deep, that a dedicated crafter could only do one/two line(s) due to time. You want them to distinguish themselves in just 1 area, but this content better be so good that it overcomes people getting upset they cannot do the other content. Additionally you will need to have a thriving economy, which means a good way to trade goods.
I had a similar experience with these changes. I logged in - initially excited - ditched my 2x crafting professions, and then went to pick up 2x new ones. I quickly did the math and thought to myself, "the more changes that are implemented, even if I believe in them (conceptually), the more I'm edged out and unable to play." It's not a great feeling. I think the crafting changes make sense, logically, but now I would need 4x characters to be independent (not the point of the game). Either that, or my wife and I would
need to run alts (probably still not the point). The truth is that we both feel that with our busy lives we're just not going to be able to play, and that's okay, it is what it is - or we'd just have to both only be 100% harvesters.
With these changes it seems even more likely that those with the time will get even more powerful/capable, and see the world as much as they want. Unfortunately, busy folk like myself are further pushed out of reach. This mechanic may be the niche; but when a team carves out a specific space for a game, it sometimes moves out of reasonable bounds for some.
I know there's more to it than crafting; we're not supposed to be independent...and, again, I agree with that to a certain extent. Your logic actually works for the game as a whole though. If you pick one of the 9 subclasses, then really you've chosen the way in which you'll be dependent on others. Choose support, you need tank and DPS to experience the truly good areas of the game. Crafting is now the same - though it seems a little different w/ harvesting taking up the crafting profession slots.
In any event, if you want the benefits of a dungeon crawl, you'll need a few other people whose skills you can't use, abilities you don't have, to get to the same end-goal. You supply a limited role in adventuring and there are play styles, tactics, and abilities that must be supplied by others...now the same goest for crafting/harvesting. For better or worse, with the exception of having two weaponsmithing professions, it seems more polished this way to me - even if more agonizingly distant.