Seriously, my inventory is loaded with tons of turn-in items, the majority of which I can't remember why I started collecting in the first place. These should be kept in a "currency" window or even the existing wallet. GW2 does a good job with this that I feel SE would do well to emulate.
We're supposedly getting more inventory space come 4.0. Sadly, that means they won't make any adjustments beforehand. It really is irksome how little use the Key Items menu sees, especially for things like Collectables, Beast Tribe tokens and etc.
I do agree it would be nice if those items were relegated to currency.