Shannon Evans who co-authored a book on local search recently published a post about how horribly wrong Google got this. The sentiment from her post was that Google is punishing people who opt out of Google Buzz.
Fortunately, this isn't true. (The following is a copy of the comment I left on Shanon's post, which she felt a need to delete.)
There's no punishment so you can relax and feel free to disable your buzz and delete your profile. Disabling Buzz and deleting your profile doesn't delete your Google Account. They are not one in the same.
What is true: Google Buzz and Google Profile are intertwined. You can't delete your profile and keep Buzz and you can't disable Buzz and keep your profile.
If you want to keep your profile (and the SEO that comes with it) but ditch Buzz, you'll have to take a few steps: don't ever post anything to buzz, remove all sites from the "linked sites" in buzz, check "do not show lists on my public Google profile" and check "do not show Google Buzz in Gmail".
Not everyone wants to turn Buzz off...they want all of it; Buzz and Google Profile to go away. Google has made that easy.
If you disable Buzz and delete your profile, reviews on businesses do not disappear nor do blog comments or book reviews. If you have claimed your business on Google Places, your local listing is connected to your Google Account not your Profile/Buzz. There isn't a "force people to use Buzz conspiracy" by Google. Not yet anyway.
Some SEO is going to be lost. Especially if you have connected all of your other sites (Twitter, Flickr, Facebook, YouTube, Blogs) to your profile. If you want to be found in Social Search, it is clearly an advantage to connect as many sites as possible. Google Profile is unique in letting you link as many as you want. Btw, there's a lot of room to experiment with SEO and local search here.
On a personal note, I don't see deleting Buzz or my Google Profile as leaving a social network. I see it as a way to stop communicating in a public way. Google social networking tools stay in tact without Buzz (Google Friend Connect, YouTube, Blogger, Reader).