That is horrible compared to what we had in GW1.
Ok, allow me to offer an example of skill unlocking. Hopefully it will clarify some things.
Note that this is true for every weapon, including aquatic ones, based on the beta that was just held.
You start with one skill (1) unlocked when you pick up the weapon for the first time.
By killing enemies you gain 20% unlock in your next skill (2). This repeats until you unlock your next skill (2). y using your now known skills (1 and 2) you gain 20% per kill in unlocking your next one (3).
If you have a onehanded weapn and no offhand - this is where it stops. Once you unlock your third skill you are done with that weapon.
If you pick up a new weapon you are back at square (1) as it were.
If you pick up a twohanded weapon you keep unlocking as above for skill 4 & 5 as well.
If you pick up an offhand-weapon before unlocking skill 3 it does nothing but look cool in your offhand.
Once you have unlocked skill 3 in your mainhand your next kill gives 20% towards unlocking offhand skill 1 (4) and then once unlocked it will start towards offhand 2 (5).
At least that is the way the game ran in the press beta.
I think that is correct, yes, you train what you use.
And I have not thought it through in detail, I am just saying that some system where respeccing was an un-annoying gold sink is, imo, a good substitute for paying for skills (which we do in GW1, but is free in GW2). Maybe a one-time fee to add a trait to an "respec pool" (i.e. a one-time fee per trait, not per "trait combination").
About the "I'm fine with x", well of course I do not love paying for stuff, either in game or afk. But I also know that if people are not getting rid of gold it will soon lose all meaning in the player-to-player market. And I really do want a new player being able to take his 100 gold and actually get something for it.
...rrrrright. Gold sinks do nothing for (or against) inflation. Consider instead the goals of an economy (both actual goals, and goals for when designing a game) and work from that.
Actual goals: Well, if we could eliminate all "money sinks" from the real world, we sure as hell would. The goal of a real-world economy is to get people what they need with as little strain on/loss to the society/participants as possible. Of course, if you look at real world economies, you see that the only "money sinks" that exist are there when people can force them in order to make money for themselves (e.g. bank fees), in which case they are not actual money sinks, which would destroy money (there are currency sinks, but that is a quite different things and are related to the fact that physical coins and notes wear out and needs to be replaced from time to time).
In-game goals: Same as above, getting people what they need. Though, in a game you often want to separate what they need from what they want. Thus, they should be allowed to very easily get hold of basic tools for playing (need), such as max-stats weapons (for their level), but things such as high-prestige gear (for cosmetic qualities) should be a goal that people can aim at.
A trader house (anonymized, spotted auction house) completely fulfills the "in-game" as well as "actual" components of the goals of an economy. It's not a perfect system, but it offers more advantages than any other: compartmentalization of players' gold reserves slows down inflation while the ability to regulate the buy/sell spread allows for actual control of it. Price transparency and fairness becomes complete. Availability on all levels (both for purchases and sales) reach the theoretical maximum. The downside is not that you won't be able to "play the market" (because you will be able to play it, of course, by speculating on goods - all goods of the same type would have the same price), but that gifting becomes impossible.
Gifting would still be possible in your system.
The complication I could see would be how to evaluate properly the worth of items, especially rare ones, and especially an item with a bunch of characteristics attached to it.
Supply/demand completely takes care of that. Once a rare skin or item is discovered and word is spread, people will start wanting that particular item. How much people are willing to pay is how the proper price is regulated nothing more, nothing less.