I use CSS and L10n ( as .properties) files a lot in my
project... But Flex always want you to compile those in SWF to use
them (as modules or directly in the main application). Why did they
make this choice ? is it that much faster ? Don't you lose almost
all the benefits of working with external data/ressources ? Those
need a recompiling for any changes, that's a shame.
The only real external ressources I can use are images (when
not used with @Embed) and XML...
It is true that these localizable resources must be compiled
into a resource SWF, but it actually is an improvement over Flex
2.0.1 where you still needed a separate SWF per language, and all
the localizable data was compiled into the app SWF.