I think DARCA is after the ability to just pay $X, and get any (currently research-able) tech next turn. Not trade for it from another Civ.
Personally, I don't want that. In reality, you can't just throw money up in the air and get a technology back down.
More importantly, I think it breaks a game balance issue.
Right now, you have to research tech - if you can just buy the tech from thin air, then there's very little incentive to ever build any research buildings - instead, you overload on economic ones. That way, you get lots of money, which is more versatile than research points, being able to buy tech from others, buy buildings or ships, and (under this proposal) by brand new tech no one else has.
Under the present scheme, you can NEVER get whole-ly new tech (i.e. something no one else has) unless you research it yourself. In addition, if you're into tech trading heavily (and spending lots of money doing it), then there is the threat that warfare and/or upset neighbors will not trade with you, under any circumstances. Both of these limit your ability to get tech. And that's a good thing. Being able to purchase outright tech break this, and I think severely hurts the game balance.
