The good news is that Steam will be discounting these bundles even further if you already own a game in it, according to a report from PCGamesN. This is based on an email that Valve is sending out to developers informing them of the change.
According to the email, “With Steam Bundles, if a customer already [owns] some items in the Bundle, they will pay for and receive only the items not already in their account. This allows the best fans of your series or franchise to ‘complete the set’ and get a deal on the remaining items in the Bundle.”
This makes sense as no one likes having to pay for titles they already own, or be forced to miss out because they don’t want to pay for the bundle. No word on how these prices will be adjusted or if it has already rolled out, but gamers looking to save themselves some money might want to keep an eye out for it.