"Primum non nocere"
Everybody can be a WikiWarden: it's not an official MusicBrainz status, but a personal decision. To become one, just add to your personal page something like "I'm a WikiWarden". Like any other MusicBrainz community member, a WikiWarden is expected to follow the CodeOfConduct.
WikiWardens are expected to be active. If you don't think you have time enough to participate actively in the efforts listed on the WikiWardening page, then you should not add yourself to the list. WikiWarden is not an honorific title - it's a worker tag you use to identify yourself and be identified by others - and doesn't grant you any specific privileges - WikiWardening is not expected to be specifically pleasant or grateful :-).
If you think something needs work in the documentation or in the wiki (something that is not style related), you may report it in the WikiWardening page, or directly contact one of the WikiWardens.