I feel that doing that for all armor sets would be a lot of work, but I do think that there is something to this in the fact that people who invest in early armor that has strong/liked set bonuses do not want to lose their investment or feel like they have to abandon the armor they have grown attached to in favor of higher tier gear.... An example: Lady Bug armor is strong and very well-liked, but it is lower tier. What if, after fighting ladybirds (Assuming they will make it back into the game) your ladybug armor could be used to craft a higher-tier version with the same or close to the same bonuses? This could be done for particularly liked early game sets that have a later game counterpart to the bug... Just so you don't lose a unique version of armor for those later game counterparts that could be included too of course.