Normalization of the database. Rather than lumping all the related elements into one serialized entry in one table, you'd make a separate table for all those possible elements, and a third table that exists solely as a link between the id #'s of the two.
I haven't really used Ubercart 2.0 for very long, but I've found that when you get into product options and attributes things get a little more complex. I think having an extra table to handle the options and attributes would be a good idea.
At the moment if I have a T-Shirt that comes in both Red and Yellow I can use the uc_option_image module to assign different pictures to the options, but I think that only gives me one picture per option. The problem I have is I will have multiple images for each T-Shirt option.
So for example the product is a T-Shirt that has the Attribue Colour and the Options Red and Yellow. Each one of those options will have a Front and Back view of the T-Shirt.
If this Attribute Option table could have a field to handle one or more images that would be really useful.