Treating training datasets as dynamic components of ML systems, along with the corresponding tooling and infrastructure, is one of the most under-appreciated points in the field today. Part of the cause, I think, is due to stigma coming from the academic side that dataset collection is a low-level problem not worthy of serious algorithmic investment (good luck submitting a CVPR paper which improves on labeling speed or taxonomy management in your dataset warehouse). Datasets are considered a given, which also has the interesting side effect of massive hyperparameter and architecture overfitting, evidenced by the recent analysis of CIFAR-{10,100} [1]. In more applied and engineering settings though, it's good to see this area seeing a lot more investment, especially on the tooling side.
[1] https://arxiv.org/abs/1806.00451