Gimp could have USE="raw" to install ufraw just as ufraw uses the gimp use flag. Reproducible: Always Expected Results: The following should install ufraw: $ USE="raw" emerge gimp
Wouldn't you then get circular dependencies setting USE='raw gimp' (when first emerging either media-gfx/ufraw or media-gfx/gimp? (The answer is YES.) In other words, why would you want to set USE=raw for media-gfx/gimp if the only added value, if such it is, were to install ufraw as well. And then, what about media-gfx/dcraw? - it has IUSE=gimp as well and does exactly what media-gfx/ufraw does with it: $ euses -cs gimp gimp - Build a plugin for the GIMP