That's it then, the forum trolls have won.

If these heavy-handed measures are being put into place to combat trolling, then the trolls have in fact won. They have caused a reaction that will enrage thousands (I'm actually not exaggerating, look at how many people play this game) and likely cause hundreds to quit.
Blizzard may be doing this to stop trolling, but in fact they are more or less capitulating to them.

Blizzard, if you happen to actually read this, take another path. Many have been suggested, and most are better than what you have planned. I would be fine with an account-specific alias that I post under, regardless of my character.
Beyond that, you say to not give out our account information. With our names on the forums exposed, and linked to our main characters, people can simply browse the forums, gather the names of people with characters they want, and then start looking them up. Finding their email address isn't too hard from there, and in most cases that's the name of the battlenet account.

So please realize that you're basically giving out the name of everyone's battlenet account if you do this. This is profoundly unwise.