I would rather they had returned the raw resources, either in finished products (bricks, bars, etc) or resources (ore, stone, etc.).
You could return stuff based on the person's efficiency in those areas, and since no Novians would be involved people would not raze plots for them unless they are builders/crafters themselves.
The Novians make non-crafters into crafters. If I were someone with several high-level adventure classes and little to no crafting experience (or a single profession, such as miner), I might seriously consider ripping up pre-built plots to get the Novians and avoid the high cost of have crafters come and build my plot.
People would be less inclined to raze a plot for resources, since they would not sell nearly as well.
In addition, it would create less of a strain on vaults that have been packed to capacity and beyond by Novians that are no longer of any value because they don't fit into the new plot plan.