Settlers has been going a long time time now and a lot has changed over the course of 3-4 years, some of the skills no longer seem to work as they first did (loot shovel) things change like a greatly reduced amount of event resources from explorers (Easter for instance) and books invested that seemed to offer good value initially no longer do. In virtually every other game I've played when significant changes happen a free skill re-set has always been offered to accompany those changes.
The free skill reset week could also encompass other changes if BB deemed fit, such as fast iron, saltpetre and titanium mines for instance, perhaps clarify and refine skills such as natures gift which doesn't actually refill much of anything, change lucky find to encompass the new materials available. Make the top skills in the explorer more balanced and maybe worth taking such as Bean-A-Colada.
BB seems determined to overhaul the game from the ground up and maybe this is an area that needs to be re-visited and rebalanced, much has been added and some things taken away partially since the science tree's were introduced. Personally I think it should of been looked at as part of the 50-75 expansion but it's not to late it seems to change anything.