Thanks for more comments!
There are some really nice items in the book and only as much space to fit them in! I simply came to the conclusion that in general, it is just a matter of personal choice at the time. All options are usually adding value to the unit. For example, a lot of people like Pathfinder on heavy cavalry. I chose Fury because I can still keep on fighting, despite some unlucky nerve tests that resulted in the regiment being wavered.
You suggested two options.
Dragonshard Shield - it is an interesting item. It suggests that you consider it worthy to have an anvil type of a unit in the army. However, as you noted, the army does not really have them. Why do you think it would be of a value to have it for a turn?
Windblast - this is something I tried before in 2nd edition in the form of the Windborn cavalry. Unfortunately, this unit is no longer available for Elves. I liked it a lot, also because it is a spell so it was not affected by cover and on top of that, you still inflicted damage. My experience, however, also showed that opponents quickly learn how to block their units from being pushed around.
It does not mean I would not like to have it. However, and it goes for any suggestion for an item and/or new unit, it also means I need to find room for it. Something would need to go.
What would you then sacrifice and why?