As of now, most of these are suggestions/my opinions. There's only one or two bugs that I can find.
1) On the installation pages, I believe you should either set the password fields (admin and DB) to use the password input type to hide the passwords OR at least mention that they are visible in the password description. Clear sight or something was a term I've heard used in the past. The reason behind this is that it's a password, and thus should be treated as one with a proper warning.
2) For the cache/cache_quickjump_1.php and cache/cache_quickjump_2.php files, I do not see an ending ?> tag. I would find this better if one is added. It's just a good habit. (I have not encountered any PHP errors caused by it, so I can't complain, but other configurations just may cause an error.) I have not checked all of the cache files.
3) If you manually enter the help.php file (with nothing after the URL), it assumes the "bbcode" section. Would it be possible to make a little index of possible items to view instead? It might help novice users, even if we aren't supposed to be there.
4) When you are viewing a report, would it be possible to add links to possible delete or just modify the post from the report panel?
For now, that's all I've found. I really like the new system and look forward to the changes you make before release (and well, ultimately, the release.)