More has changed in version 7.0 than just modularization. The last X.org version was 6.8. The new versions are 6.9 and 7.0. It is not like the last version (6.8), but is identical to the new 6.9 as far as new features and bug fixes are concerned. It is a major release because the build system and structure of the source code changed significantly.
For the end user, modularization means little at the moment, but should help speed updates in the future.