vector: Apply content text style via .mw-body-content instead of #bodyContent was just merged and claims «The use of classes for content styling has been recommended and generally agreed upon, specifically in the context of the RFC about scoping site CSS» in order to «finally liberate content styles from the notion of a singular body div on a pag». Reviewers pointed out some possible side effects, they may want to elaborate.
However, the RFC doesn't say anything about this yet, can it be updated? Can the alleged problem can be solved "simply" by using classes more? It's been a MediaWiki development mantra for a while to always put new stuff in a class so that it can easily be overridden (also on wiki) and reused.