Add a marker annotation (e.g. @Enhanced) to classes that have been processed using the "enhance" goal of the Maven plugin. When the plugin runs again, e.g. during an incremental build, this marker could be detected and the reprocessing could be skipped immediately. This should improve the build times in Eclipse.
Since the annotation has to be in the class file, it has to be added to the uimafit module. If it was only in the uimafit-maven-plugin, the enhanced classes could not be loaded unless that module was on the classpath.
... well, actually I think they could be loaded, but we've had issues with findbugs annotations that Eclipse couldn't resolve when analyzing the class file, so probably better avoid such situations (cf. https://code.google.com/p/uimafit/issues/detail?id=78).