A witness job is to secure the network, produce blocks, and provide a price feed. Witnesses have the power to approve or deny changes to the network and should have the knowledge to make that decision intelligently and not blindly. Unfortunatley Steemit Inc are the only ones who make hard forks, so there isn't a lot of choices to be made, although a hard fork has been declined by witnesses in the past.

Many witnesses do more, many do less, some aren't even present and just collect the rewards.

The ones that do more are very passionate about STEEM as a platform and a currency. There is a lot that goes on behind the scenes no one sees.

Unfortunately, many see witnessing as another way to generate a revenue stream and treat it as such. This encourages users to become witnesses without the technical competence required by a witness or the passion to make Steem better.

There is no doubt a witness is a politician, and needs to campaign as such to get anywhere, but there comes a point that only one vote matters as it controls who makes it past a certain point.