I am not an ETN investor or ICO buyer, so I have no stake, you are all free to disagree with the following:

It seems like one way to avoid a crash on release of ICO funds is to tier the ICO fund release.  For example, release half up front, and half in another month.  Some ICO investors may not like that - I would totally understand if they dont want to wait more - but it might be better for all of them because it reduces the risk of price crash.

Thinking about it more, the current supply is also ~5 billion, so there's no obvious reason why releasing the 5 billion additional ICO coins should do anything worse than (temporarily) cut the price in half.  Everyone knows those ICO coins exist, so releasing them shouldn't change ETN's market cap.  Thus, the price should at worst go to half of what it is at the ICO wallet release (before any further movements), which isn't all that bad.  This is just a theory, of course.  There are other theories to cut both ways.  Some might say that the current price should already account for the sell pressure from ICO coins - therefore the price should fall by less than half.  Others might say that ICO investors are more willing to sell than miners because they already have a big return, in which case the price might more than halve.  I think overall half is a good expectation, but this is just a layperson's analysis.  Do not invest/mine more in ETN or any currency than you can afford to lose.