I agree with the vast majority of the first section, the game would simply work better if these these rules were transferred directly from 5e. The game would also feel like a D&D game, both viscerally and visually. As far as the items, and I hate to say it, but I don't think many can be salvaged in any real way. Magic items in a D&D game should feel like D&D magic items. However, the philosophy of design is not being used when making new items.
Some uncommon items can be nerfed, and some uncommon items can work within the context of lower level, an area that one expects level four and five character to be in could contain them. Most of these uncommon items that would be appropriate have specific uses in specific situations, give the wielder something cool to do once per day, and most often don't reproduce spell effects of greater than the party can cast at the time. They can simply serve to spice up some of the encounters. One doesn't need to vomit magic items all over the player, many times less is more. The items become more precious and cooler when they are fewer.
