There was recently a bug report about a potential exploit on changing the font size using HTML to something huge and affecting the page layout. It appears that this bug has been fixed by dis-allowing the use of the size attribute in a font tag. However, this presents new issues...
First. The only way to change font sizes now is to use header tags. This presents three issues:
1- Header tags add padding, meaning there is blank space below the line enclosed in header tags. For formatting purposes, not everyone may like that, it adds a ton of whitespace. SOLUTION: Update the css to remove the padding.
2- You are now unable to change text size mid-sentence. Using header tags forces a new line.
3- By default, profiles center themselves, but the header tags left-align. SOLUTION: Update the css accordingly to center-align header tags, or left-align paragraph tags and/or body tag.
Second. Likely unrelated to the font-seize issue, but most likely due to whatever changes were made in HTML handling, tables now have borders. Even with a border=0 attribute borders are present.
These are just a couple things I noticed from my own profile, though there may be other issues as well.