The small amount of features and fixes included in this update speaks for itself.
A major 10.1 update is probably on it’s way when ready.

Logic Pro X 10.0.4: Release notes

Symptoms

Logic Pro X 10.0.4 is an update to Logic Pro X. Logic Pro X is a new paid version of Logic Pro.

Resolution

For more information about Logic Pro X, please see www.apple.com/logic-pro.

Logic Pro X 10.0.4 update

• Includes a change that allows Logic to properly open GarageBand X projects.
• Fixes an issue in which the Mixer might flicker when scrolling up or down in OS X Mavericks v10.9.
• Resolves an issue in which EXS instruments created with third-party applications might exhibit unexpected voice “stealing” when played in Logic Pro X.
• Resolves an issue in which the Tuner did not display correctly on Retina Displays with OS X Mavericks v10.9.
• Fixes an issue in which Logic Pro X did not correctly display track icons in projects imported from GarageBand 2 for iOS.