I don't think the shop is intended as a source of upgrades for early gameplay (it most definitely is a source of upgrades later on, but mostly for newly recruited heroes). I view it more as a source of money early on, a place to sell all the little things you've been collecting while exploring that you won't be using. Plus, they also added a Trade/Shop button to switch between easily. I'd like to see unit items instead of things only champions can use. This could cut down on some of the higher costing units one can produce later in the game.