I think it would be more ideal to create a new widget that does what you're looking for -- rather than modify the TextBox widget. Others have asked to be able to output Google AdSense code or other pieces of Raw HTML into widgets. It never works
very well with the TextBox widget.
A new, very simple widget could be created that has a multi-line textbox in it (not tinyMce), and raw HTML would be pasted into the textbox. I know this widget would be perfect for the AdSense and other Ad people, and sounds like it might fit what
you're looking for too.
I haven't used the
forced_root_block option before, but this option might not work well for people who are using the TextBox widget for more "regular" straight forward text editing. Having <p> tags or <div> tags or other block level wrapping for
content probably is what more people need, rather than don't need.
Also, if we made the first change you propose (removing the <br />), this will essentially change the rendering of text for people who are already using the TextBox widget with Show Title turned off. This isn't a big problem, but we probably
don't want to make a change that will impact a lot of blog layouts for one request (absolutely no offense intended). I just think it makes more sense for a person to make a small tweak like this with their own installation. This is one big advantage
of BE.NET being an open source platform.
P.S. The name of the new widget I mentioned with the multi-line textbox can be called the "Literal Widget" since it simply outputs its content literally.