No. We vote yes or no on whether to accept or reject the hardforks, but the development team (Steemit, Inc.) is who decides what to put in the hardforks and does the coding. The witnesses have a voice in the process, but it is a limited power.

The change that I developed to increase the SBD printing is one of the few (if not only) times that a witness has actually done coding to make a hardfork change.

We are working towards having this become a more regular thing, but there are a lot of complexities involved in making it happen. For now it is mostly up to Steemit, Inc. to decide what goes into the hardforks.