Upgrade items like champions

Maybe instead of combining different items and wasting time seeing their effects, looking at a table, memorizing, and so on, why not just have it that if we get similar items, they simply upgrade? Also nerf items while you're at it. They should provide basic stats, but not act as if they're passives. Some items are better than actual passives, which is rather sad. Items should not be breaking champions, but rather boosting them. This is the only auto-chess where champions break based on the items they obtain. Also all items should be feasible with all champions. For example, there should be no champion that does not have mana, so everyone can benefit from it, or simply remove the mana item.