Process the captions as video files on a dedicated subtitles track
One caption should be processed just as a standard video file.
Instead of a new "captions" file in the bin, we should create a "caption track" on the timeline.
This subtitles track would appear as some sort of "S1" track above the video tracks. It would be processed as a video file dedicated to captions, the same way you process the submix tracks for audio.
Inside the different subtitles tracks, we would be able to interact with the different subtites the way we interact with any other file in the timeline : multiple selections with shift, selection of everything after with "A", etc... without having to double click on the captions file in the timeline in order to move one subtitle at a time.
This way, we could have multiple subtitles tracks, easy to access and waaaaaay easier to manage.
The way it is now, I don't see a reason for anyone to use the captions except for "I don't have any other solution right now".
I beg you, change this as a priority.
It would really make Premiere Pro so much better. There is no need in improving the actual tool if you don't fundamentally change the way we interact with it.