Most of Hudi content is now hosted on the project site or the Github repo. This wiki is not updated/maintained actively.
RFCs are the way to propose large changes to Hudi and the RFC Process details how to go about driving one from proposal to completion. Anyone can initiate a RFC. Please note that if you are unsure of whether a feature already exists or if there is a plan already to implement a similar one, always start a discussion thread on the dev mailing list before initiating a RFC. This will help everyone get the right context and optimize everyone’s usage of time.