I've noticed a trend in the past 2-3 worlds where you can take second tier gear and some reagents and craft it into gear identical to the best dropped gear in the world. However, this trend hasn't extended to the universal gear; that's only available in dropped form. With the new level 150 mastery changes, universal gear has become more desirable, so I think that the availability should be expanded with crafting recipes as well.
I agree with you 100%. We should have school combination gear available to craft throughout all levels. For example, if a life wizard has a storm mastery, they may want clothing that keeps their best life related stats but also bolsters storm statistics. A lot of the more popular secondary school choices should be a consideration. For example, Storm main with a death mastery is common, so that should be an option. Any primary with a storm secondary should be an option, since storm's raw power is desirable. Those are the prioritizations KI should make before creating a combination of each school with each school (which would be an immense list of gear). And I think the secondary statistics should be half as good as the main statistics.
So for instance, let's say a storm wizard trains death as their secondary or myth. At the legendary to archmage level, storm can achieve some pretty good damage via waterworks gear. Anywhere from 85-110 with certain pets and jewels. I think the death boost on the crafted storm clothing should be anywhere from 50-60 to make drains viable in combat. Some considerate thought would have to go into something like this but I think it is doable.