I have created a very simple module that corrects bad interactions of other modules.
I am the maintainer of Slideshow Creator, and users are complaining of its interaction with the line break converter filter (LBC). Slideshow Creator (SSC) translates a special code in any text field into a slideshow, but the codes end up long and complicated and so users want to insert line breaks to make them readable. If LBC is placed before SSC, it changes those newlines into p and br tags and destroys the slideshow code. OTOH, if it is placed afterwards, due to what seems to be a bug in LBC, it inserts a spurious p tag inside the generated slideshow code. In short, the only way to use these two together is to put LBC first and write an unreadable one-line atrocity for the SSC code.
Clearly, there might be other filters with bad interactions, so a general solution is needed.
THE PROPOSED SOLUTION
My new simple module provides two filters and an admin page. On the admin page you specify regular expressions for content that should be shielded. Then the first filter finds and removes any material in the text that matches any of the regexes. You then run the problematic filter, which can't mess with the removed material because it isn't there. Finally the second filter replaces the removed material.
The way I use it to fix my particular problem is to use the regex from the SSC filter. It removes the SSC code, then the LBC is run, then the SSC code is replaced and the SSC filter runs.
This is a very basic filter, but it seems to fill a need. Any thoughts?