I find myself, now that I've been playing Warden specifically, having to scrap gear that I'd like to keep for aesthetic purposes. On my warden I have only 3 helms/arms/chest pieces. The rest of my gear is all weapon sets but I cannot keep even half of the weapon sets available at the time of this posting. I would love the option to collect the sets without having to choose which ones I like. As you level your heros into the 15+ range, there are not many unlocks to look forward to. And as is a popular hobby of many gamers, farming for gear you'd like to collect gives players "something to do" on top of the already lengthy "grind" that some people enjoy.
I propose allowing players to "buy" extra inventory space on a per hero basis. The option to do so can be unlocked at a designated rep level and be multi tiered. For instance 10 extra inventory space for "x" steel. 10 more for "x" more steel. Or even allow the space to be purchased with scrap, potentially at a very high cost.