Well you may get your wish, but with "lots and lots of downvoting", you may lose lots and lots of users that won't come back and will all tell their 10 friends to steer clear as well...

Regarding the company comments etc... I think you need to leave the downvoting/flagging to a few possibly elected moderators. Let the community upvote what they like and then moderators in each tag or community will decide if there is abuse being done. There are many spin offs of this idea, but it's just spitballing a bit and throwing out some ideas... I think overall though, letting the community at large run free with downvotes will guarantee a worse user experience for the vast majority of users. Like you said, downvoting will be the norm, so will flag/downvote wars, and those make most rational people upset and angry and they will vote with their feet and leave the negative environment, which will kill this place. Just my 2 cents.