In general a good trading guide but I think you forgot some important things:
Couldn't disagree more. If you don't have a DMU, those can really block your progression in the game, specially, like in my case, if you are more PvP oriented. I personally have traded for components a lot of times until I reached higher levels when I don't need them much anymore.
This whole section I would rephrase. Nobody can define the value of anything in barter trading. You can only talk about trends, since the value is essentially subjective, specially when you have a whole lot of collectors in the game. I've once even found someone willing to buy a black medical kit with only negative bonus!
The fact that people are always putting a virtual price on items is in fact wasting trade if you ask me, since it's almost impossible to buy "regular" stuff because everyone is asking for rares and uniques in return.
In regards to your disagreement with componenets and resources, fair enough. I just remember spending fuel and trading for those items and deeply regretting it for the fuel.
Next, the whole point of the "Valuable Items" section is not to put a price on something, but rather to let new players know what is sought after in the game and what they should be on the lookout for. I tried to not include prices for things as much as possible because as you said, prices are so subjective and hard to determine at any given time.
It's to show new players that they should not trade that shiny, brand new, unique waki away for a two higher level rares. Just to give perspective and help out with making clear on what *most* high-roller traders and regular baterers look for and what's valuable in game.
Thanks for the feedback.