LWC Browser/VS Code Preview
Single-component preview without deploying. Faster iteration, better inner loop. Probably the highest-impact dev feature this release for UI developers.
API Surface Improvements
Expanded REST endpoints, better error responses, richer Bulk API 2.0 capabilities. Integration developers get cleaner contracts. Worth re-checking your API usage for new patterns that simplify existing code.
Apex Productivity
Language improvements, testing ergonomics, debugging enhancements. Incremental per release; cumulatively meaningful. Check the developer release notes for anything that affects your style guide.
Deployment Tooling
SFDX and sf CLI continue maturing. Git-first workflows get smoother. Preview changes before deployment; deploy specific metadata with finer control. DevOps teams see continued velocity improvements.