1. New Theme Installer routines
2. Add CodePress syntax highlighting to Theme and Plugin editors
3. Add Documentation(function) lookup to Theme and Plugin editors
4. Use “Custom Header” for menu text and revise Default theme to reflect change
5. Separate Comments into a separate postbox, from Discussion postbox, on the Edit Post screen
6. Make tags accessible without Javascript on the edit screen
7. Don’t ask for confirmation when marking a comment as spam
8. Don’t notify post author of own comments
9. Fix comment paging for static front page
10. Allow the dashboard widgets to be arranged in up to four columns as set via the Screen Options tab
11. Make titles into links in Dashboard Right Now module (this was in 2.7.1)
12. Improved Admin icons (grey-to-transparent shadows)
13. Update Blue Admin Color Scheme
14. Press This improvements UI, quoting fixes, plus ability for Contributors to use Press This
15. Add a Cancel Upload button and a Delete link to Administration > Media > Add New
16. Add column “Rating” in Administration > Links > Edit
17. Improve installer to help people entering wrong email addresses
18. Improved Widget user interface
19. Allow editing of all plugin files (Ticket 6732)
20. Improved Plugin search (this was in 2.7.1) on Administration > Plugins > Add New
21. Per Page option for plugins
22. Move “Install a plugin in .zip format” to new Upload tab under Administration > Plugins > Add New
23. Show absolute date instead of relative date for scheduled posts
24. Fix tags suggest for post quick edit and bulk edit
25. Permalink editor changes and fix for pages
26. Autosave post/page when pressing Control/Command+S
27. Add toggle all button to the Gallery tab in the uploader
28. Support more than one gallery on the same page
29. Add per page option to Screen Options for comments, posts, pages, media, categories, and tags
30. Overhaul of LiveJournal importer (also add define WP_IMPORTING)
31. Import category descriptions for Administration > Tools > Import > WordPress
32. Show Tools menu for all users so they can access Turbo
33. Check for new version when visiting Administration > Tools > Upgrade
34. In upgrade process, provide better explanation for database upgrade message
35. Fix most popular link category list
36. Add description field for Tags in Administration > Posts > Tags
37. WAI-ARIA landmark roles to added to WordPress Default theme
38. “Choose a city in the same timezone as you” for Timezone in Administration > Settings > General
39. Remove My Hacks option from Administration > Settings > Miscellaneous
40. Hide email addresses from low privilege users on Administration > Comments
41. Allow case-insensitive logins
42. Login and Registration pages noindex followed
43. Give login screen proper iPhone viewport
44. Enforce unique email addresses in Add/Edit users
45. Make user_nicenames unique during registration
46. Add “Send this password to the new user by email” option to Administration > Users > Add New
47. Don’t set user’s Website url to http:// in Administration > Users > Add New
48. Add password strength meter to Add User and Edit User
49. Hide things that need to be available to screen readers via offscreen positioning
50. Use invisible class for hiding labels and legends
51. Use a semantic class name for text targeted to screen readers

Hope we will get a lot more new features in upcoming versions of  WordPress. This will help a lot in WordPress Customization and Development.