Not following why branches in git are lighweight affects anything ? its what makes things tolerable right now; but would be even nicer if we didn't have to do it so often ;)
About components then I don't see any changes needed in the components that does not affect the eclipse related code - what are those ? The only change I can recall is the parent pom reference but that is just an old/legacy requirement. It does not need to be updated between builds.
And yes we can still compile from the tag/branch - to ensure things are building but if nothing breaks we don't need to update the actual published plugin.
That is what using Tycho's "Reproducible Version Qualifiers" is for, see wiki.eclipse.org/Tycho/Reproducible_Version_Qualifiers