With the recent addition of levels 11-20 for furniture and the changes to the drop rates in boxes, upgrade mat demand is at a high. While the addition of furn boxes and dismantle pieces in free boxes helps players accumulate furniture pieces, it does little to help acquire the red/blue/yellow required in massive quantities to keep leveling. I have a few ideas for adding more R/B/Y into the game. A simple fix would be adding them to boxes, or perhaps removing event drops from free boxes and replacing it with R/B/Y mats, although this would be quite abused by box farmers. An alternate solution would be purchase of R/B/Y via either traders tokens or aqua / inferno. If there are any other ideas feel free to post, at this point i, and I'm sure many others, would be willing to drop nobs to open a box that solely contained decent amounts of mats.
They should just drop the rarity of walls / floor and banner back to rare again. That would solve the problem. Used to get one almost every other chest.