I agree. I think in the next Version the horadric cube will be integrated into the inventory. Already have a nice concept for that... This should eliminate swiping a lot!
i'd suggest: different "Tabs" for rarity or the option to set sorting options by stats ( like dmg, attackspeed or exp boost)
When I designed the current inventory, I had in mind that a user would have no more than about 7 cards in hand. With more cards it's getting more and more complicated. One idea is to make card gambling much easier (swipe up gesture to 'trade' a card that is no longer needed). By that it should be easier for players to maintain a fluent stack of cards. This trading mechanism will be integrated into the game and shall work for all card types! Also, right now in the endgame you get that item flood because it doesn't make sense to gamble those (rare) items in the horadric cube anymore... Right now I am thinking about the following concept: 4 rare tower cards -> 1 rare item card 4 rare item cards -> 1 rare potion card 4 rare potion cards -> 1 rare tower card (this option probably won't be used a lot ^^)
add towers, items and potions that are only found from this including uniques! Just imagine you sacrifice FOUR uniques for a CHANCE at a very special ONE!