Some things that I feel Gems of War really needs to improve it some ways.
Gift Items. Just like many other FTP games like Warframe I'd like to be able to buy something from the "Shop" or "Offers" tabs and give that away to anyone on the console. Example I wanted to give my guild mate who just started subscriptions to Gems and Souls for $4.99 each last night and I had to send him money through PayPal in order to accomplish this. This should be an easy thing to implement and will drive up sales so make it happen!
Troop Details / Information: This is mainly for "Arena" but it can be implemented for Chest opening as well. After the Arena is complete it gives you the option to purchase the troops you used but it doesn't tell you if the troops are new for you or if you have (and how many) copies of each you have. This information will impact the decision to purchase and should be known easily with out some separate tracking sheet by the user.
Chat Tabs: These should have suggested words pop or even better give you previous messages as a default to select (or auto fill) like many other games and the PSN Chat interface on the console. Retyping the same guild recruiting message over and over for global chat is painful right now and it shouldn't be.
More Daily or Weekly tasks. The 4 daily tasks need some variety which has already been discussed but I also think we should have more and I'd like to see 2 to 4 "Weekly" Tasks and possibly even a "Monthly" task to strive for to add in more to do in game.
Troop Upgrades. This is OK as is but to make it better you should be able to filter for "Upgrading Traits" or "Upgrading Ascension" I find it's very time consuming to "Ascend" 1 troop of 20 and then have to scroll all the way past 200 green plus sign "cards" to find the next blue plus sign card to ascend.