Thank you for these feature requests. I have logged them in PITS where you can vote and raise their priority.
1) To add search option in the document link widget - ID 6337
2) To display categories/tags next to the document in the link widget and in the Insert Doc widget - ID 6338
Your Telerik points have been updated.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items