2. source lookup (back and forth). Now when you do source lookup, it should be integrated properly with language quirks like virtual-env in python
3. proper and standard keyboard shortcuts ( NOT like intellij)
4. Good vim support
update: 5. cross-domain support. e.g if you're full stack developer and use rails as backend, IDE should support both rails and front-end stack. Basically front-end stack is mandatory these days for web framewoks.
6. project wise search
7. file search.
Intellij has done lot of good work.
1. but they utterly fails in keyboard shortcuts (which are not consistent with other tools like browser)
2. their IDEs are in java and damn slow
3. very poor cross-domain support. now this is complicated because of complexity of modern programming.
If you guys are planning on any IDE, ping me. Will glad to help.