Hi Oshyan, 
I really like the idea but…
Topic title is not unique so now when you search a topic you have other additional informations such as tags, categories to help recognize it more but inline might be too crowded and sometimes too many topic match your search to filter it inline.
Other thing:
When you use this panel to insert link you have to confirm your choice with a button click which is super useful I think.
In inline if you missed the correct topic you have to delete too much and maybe there will be more broken format links than now.
Maybe there is a good way to make it simple and fast but now I think the panel solution is faster and more user friendly.