I like the idea of re-opening old session for QOL reasons but it would be a bit tricky to implement since the shell is terminated when ST is closed. We could probably track the current working dir and try to re-open session but running programs would probably be lost.
Opening file paths
Finding file paths and opening them in ST would probably be do-able (and quite relevant) so I'll definitely look into that at some point
Color support should be working with pyte which is the terminal emulator thats being used. If enabling colors through settings does not work for you I suggest you create an issue with some info about your setup (ST3 version, bash version, etc.)
Selecting/copying like regular buffer
As described in my development plan some copy paste functionality is to be included. I imagine the copy functionality being implemented somewhat like you describe. That is, you would enable some kind of "edit mode" where you can move the cursor freely and use your regular ST keybindings.
The input goes straight to the shell so this is not really a possibility. It's possible that the plugin could support some kind of command staging mode but that would be extreme QOL.
ST3 syntax coloring
This might actually be quite easy to implement. I'll have a look at it when I get a bit of time.
I have a working PoC on another branch. The best terminal emulator I could find was pyte - but it only supports showing a screen of characters. The way the PoC works is by using pyte's history screen. This works great but the ST scrollbars are not being used. I would like to implement a sliding window approach where the actual ST buffer is used as history but this will take some time and consideration (and probably some restructuring).
Thanks for the comments guys.