The problem you're having is only partially due to your use of Imprint
MT Shadow, which by the way is neither an outline font nor a shadow
font but more commonly described as engraved or open. Either way,
you're right - the glyphs are much too complex for this application.

You haven't said whether your output will be used in print media.
computer screen, or a movie theater. It makes a difference.

Type styles that rely on the significance of both the dark and light
portions are not suitable for graphic backgrounds, and this is even
more pronounced on screen than in print because of the much coarser
resolution.  In your example, I didn't even SEE the text over the
houses until I re-read your message mentioning the "third placement"
and "fussy background".  The discrimination between the text and the
backround is lost because of the color similarities and is made even
worse by the text size chosen relative to the size of the elements in
the image. If they're that close they WILL get confused and lost.In
practice, you want to use dark lettering on light backgrounds, light
lettering on dark backgrounds, and lettering that's large enough to
create a size contrast with the background pattern.

Closed captions on TV are always placed on a consistent background to
avoid just such problems. GOOD movie subtitles either do the same or
vary the text color intensity with the background. There's nothing
worse than seeing black subtitles for a foreign-language film for a
crucial scene taking place inside an unlit coal mine at midnight.

There are plenty of plainer fonts available, both pay and free. With
free fonts there's the very real danger of getting what you paid for.

A small drop-shadow or thin outline can help maintain contrast;
mis-used, though, they can also introduce jarring visual elements.

I'd suggest finding some everyday magazines and looking at how the
advertisers present their messages. A good graphic design book could
also help.

 - Character