Alright, my two cents so far:
First off, I dig the Vasari.
That said, I too am having some issues with the new Black Market. I've grown rather accustomed to having a metal/crystal superiority (and credit inferiority), and being able to rapidly liquidate those assets (which is something I had to do frequently to counter seemingly lousy credit production values compared to my opponents).
Currently - that is no longer anywhere near as feasible a solution as it used to be. Selling them to the black market at any time other than a boom, is just plain foolish. While I understand you might have meant for that to be... it's a bit difficult to catch.
If you are going to make a Black Market that is far more dynamic, you really need to add a means to track the fluctuations in the market, that does not involve watching a fullscreen display to the detriment of all other aspects of your empire. Because honestly, having to switch to a fullscreen display to monitor the situation - at the expense of controlling anything else - is just stupid (no offense).
Those little updates on the alert windows on the lower left? Those are a bit unwieldy, and honestly very hard to notice (they need a good sound alert or a brighter flash, or something?). Not to mention if the market booms, the message is usually replaced almost instantly with something else. Yes, I'm aware you can see the messages at a glance with a mouseover - but that doesn't mean much when they just keep on scrolling into oblivion. Also, some sort of timestamp and an in-game timer display would be nice to help keep things organized (I didn't somehow miss one did I?).
All I am asking for, is a tiny little ticker or graph... Maybe 1.0 to 2.0 centimeters tall, and 3.0 to 5.0 centimeters long (I have no idea what that is in terms of pixels... just something around the size of a pinky finger on screen is what I'm talking about), that I can stick maybe in the upper right corner underneath the top toolbar, maybe make it dim and transparent so that it is readily readable, but not too distracting.
That's all... just some miniaturization so that I can multitask a bit better. I hate missing precious oppertunities because my attention is needed on a micro-intensive battle that I would have to abandon completely for a fullscreen display that could be shrunk down to almost nothing! Seconds matter

That or just up the base amount on the sell to the black market - since putting stockpiles on the black market as opposed to selling them directly no longer seems to really matter, as by the time you hear of the boom - the player who is buying has already purchased, and your supplies will just sit there depreciating.
One last thing: you really can get way too many supplies at far too low a price by clicking really fast... and the price booms really don't last quite long enough without considerable interaction with the market - which is nigh-impossible on a small match (2 to 4 players). I don't rightly understand why the Black Market... a means of obtaining things questionably that you would not normally be able to acquire... serves the Buyer so much in this game, shouldn't it favor the Seller?
EDIT BELOW:
Eh, I just don't think you will get the Black Market quite right until you make the amount of crystal and metal it starts with finite. If you really want it to be fair(ish) and impact the game well... you need to start the Black Market off with a finite number of resources, that increases at an initially slow (yet scalable) rate.
Make the amount of resoruces (supply) present, depend primarily on the stockpiles that players contribute for sale (as opposed to direct sale to the black market). You could perhaps make direct sales to the black market be considerably less profitable (although immeadiate gains) compared to the amount gained from someone buying from your stockpile, and have it increase the rate of resource generation for it (temporarily) without actually increasing (directly) the amount of supply available (instead of gaining 100 resource, it just ups the rate regeneration).
Allow price to fluctuate based on supply versus X number of units sold in Y amount of time, and figure in the current rate of resource generation somehow; and then supply and demand economics can really kick in - and the market can crash, although over time even with no player infusions, it should be able to regenerate. Here's a thought - have pirates influence the supply. Every time they kill Trade Ships, Trade Ports, Refineries, or Refining Vessels - have the amount of supply increase some. Hell, it even gives you a reason to add fun changes to how pirates work (arrr!). Heh, a good pirate raid could put a cramp in your Black Market profits

!
Eh, just a though.