When I remember using hard glass ketchup bottles instead of modern squeezable ones, however, it does seem like we'd be losing something here. Some variation in container design is valuable. Pushing the standardization via a tax on non-reusable containers would probably be the best option, though you could also imagine some system where you add an exception if the manufacturer can justify why they need to do something unusual.

While the main benefit here is through more efficient reuse of materials giving lower packaging costs, there's also a gain from reducing competition over branding. Manufacturers are often competing over the same number of sales, trying to attract buyers through something unique in the appearance of their product. Just like how laws limiting cigarette advertising accidentally made tobacco companies more profitable, limiting this channel for product differentiation probably would be helpful to neutral for manufacturers.

It would probably be best to try this at a smaller scale before rolling it out for everything. For example, you could start by introducing a standard 250mL (1C) container, and have the tax for non-standard containers only apply to products within a certain range of the sizes that have been standardized so far.