@iamthealex Beats are lightweight shippers and we try to keep it that way. Beats should do everything which is critical to be done on the edge node. For example filtering is important to reduce the number of events that are sent to reduce network traffic. If we start adding more and more processing features like grok to beats, beats will not be lightweight anymore.
We are aware that some people would like to do the groking on the client side. Our current recommendation here is to use LS on the edge nodes.