I think the timing of the global events are key here. When so close the double XP event, the attraction for this global event wanes significantly. The chests are useful as you get several potions. For lower levelled players they can provide some mighty boosts to their hunts and other activities.
I would like to see fragment stashes but with the contents significantly higher or maybe stashes like we receive from the fragment global events with a range of fragments in each chest.
Set items would be good as the current items are pretty much useless apart from the few that are used for inventing. Sadly as things progress items and other things in the game become out of date so an update would be appreciated.