I couldn't think of a better title. Anyways, my idea is simple: an upgrade that gives more cps depending on how many upgrades you have (such as cookie production multiplier +1% per upgrade). There are a lot of upgrades that are basically useless depending on your playstyle (for example, if you don't click often, then there's no point to purchasing the clicking upgrades besides from completionist reasons, and if you use golden switch then the golden cookie upgrades are also useless), so I think that having a guaranteed bonus to your cps no matter what upgrade you're buying would be nice. It wouldn't be op either, because there are only 356 upgrades in the game currently, leading to at most a cookie production multiplier of +365%. This pales in comparison to the massive bonuses caused by prestige levels and the milk upgrades, so balance is hardly an issue.
Another one bites the dust