TinyMCE breaking HTML arbitrarily

We have installed a blog. Because the site’s owner does a lot of design on the text itself, we activated several options, e.g. the text colour and font size drop-downs.

However, TinyMCE is proving impossible to work with:

– Line breaks are deleted
– Line breaks are not generated as <br> elements, even though force_br_newlines is activated and we tried using Shift+Enter
– The mere editing of text that has been formatted (seemingly) arbitrarily strips all formatting, leaving broken content in its wake.

as a result, the WYSIWYG editor is almost unusable. I’m baffled as to why – seeing as this is the most basic use imaginable, isn’t it? We’re not working with fancy images or layouts…

Does a general fix for this exist? Are there things we can do to remedy it? I’ve looked into TinyMCE advanced but can’t see it doing any better in these very basic tasks.

Any input would be much appreciated!