Hi
few my sugestions:
1. the default option in serach engine should be "global". In 90% cases I have to change it on global

2. After added new task it would be better if you show this new task (now you show the list of tasks).
It will be realy easier to add some subtasks, comments or to check if all is ok.

3. All Comments to tasks forwarded to many people should be showed to all peoples who have access to this task. Now only comments from author of some task are showed to all collaborators. When someone who have to done this task add comment, only author of this task see this comment.
Its realy hard to team work without normal comments.

4. It will be great if person who add new task for himself would have some option to send an automatic notification to someone else after completing this task. Now I have to assign new task to my workers by myself if I want get notification.
I would prefere told them whot to do, and they shoul add some new task adding my as person who delegate them this task, or adding some nottification to my after completing.
Now I have to add all tasks to my workers manualy by myself. Its take a lot of my time...

Pealse - consider to make this changes.
Or add them as an option in preferences.

Best regards,
Lukasz