Nielsen gives "free" 12+ share and cume in diary markets, and limited daypart rankers without shares. Anything else is prohibited in each station's contract. Any violation that Nielsen hears about is generally followed by a "lawyer letter" from them.
It is as good a methodology as is available anywhere in the world today for medium and smaller markets. It is not and never was "flawed" for its purpose which is to give a metric to advertisers. And, as far as "updated" Nielsen is moving the diary to an online mobile app which will make more immediate data entry easier for participants.
The biggest issue for any survey or ratings or research company is finding participants, not the methodology. That is where technology comes in to create new methods of locating, contacting and "selling" possible participants on being part of a project.