This is kind of half an idea, because it certainly would need elaborating:
But in my fantasy football league we now have what's called a "window day" on trades.
What that means is that after I announce a trade, there's a day for other owners to beat the offer.
So let's say I traded Tom Brady for Roscoe Parrish - there's a 24 hour window for people to tell me I'm stupid and offer much more for Tom Brady. At the end of the period I can either keep the original trade, or pick the best offer after that.
The advantage here is it takes away the whole "Wish I knew (player x) was available, I would've offered a lot more" argument, and curves out the lopsided trades.
Obviously for the CBDraft things are a little more complicated, but I think there's something in that idea that could work here.
The problem I see with this idea is that lots of trades involve draft picks, and are done while "on the clock". There's really no practical way to have a waiting period that I can think of. Plus, it would leave GMs with some roster uncertainty. For instance, what about the following scenario: Team A needs a SF. Team B and Team A agree to a trade for a SF. However, the trade is in limbo, and Team A is on the clock with its next draft pick. It's faced with the scenario of having to choose between picking a SF (and potentially having two players at the position on its roster), or passing on the SF (and potentially being left with nobody at the position).
It's an interesting idea for non-draft pick trades, although it does take away another bit of the "realism" from the game, and seems to punish aggressive GMs. If this rule was implemented, GMs wouldn't have as much incentive to work the phones; they could simply wait and attempt to "match" another offer.
This is something we should think about more. Any tweaks that could address the above concerns would be appreciated.