Adding subtitles to videos was very complicated before the update. On the first look, it supposedly got a lot better, except so much is buggy in the new caption tabs, especially the Text panel. Maybe I'm doing something wrong because this new workspace is very different, but the caption blocks often become unclickable and I have to change panels and click everywhere for it to allow me to click and change the text again. I can't find an easy button where I can add a new block on the "+" button directly ahead of the current text block unless the playhead is completely outside of the current block - and then I have to drag it back so it touches the previous block, or right click to find the option to create a block directly after the current one, and both are really getting in the way of my workflow. Another thing is on the new Captions workspace, the "Text" panel opens up at first as usual, I add the first subtitle, and I delete it, and the panel just goes blank. All of the buttons are missing, there's only the title of the panel and a gray area. All of the other panels keep working fine when this happens, and so far my only solve for this was closing the project and opening it again, which isn't a viable solution because this issue has happened a few times and repeating the proccess takes way too long. Many other little things are really stressing me out and delaying my work schedule, and I'm considering downloading another program only for captions because in this rhythm I'm not going to meet my deadlines. Windows 10 Intel Core i5 NVIDIA Geforce and Intel Graphics.
Editing, Error or problem, Freeze or hang, User interface or workspaces
As you suggest, I believe it is the combination of the new workflow - and we can help you with that - and a few areas that have bugs or the design is not what you may want. And the devil is in the details.
In 15.0 (fixed in 15.1), when you select captions, the Text Panel may scroll to the top. There is a workaround for this, that, even in the fixed version, is a better workflow. See Matt Young's post here: